Package Instance

Kirby vulnerable to path traversal of collection names during file system lookup
The missing path traversal check allowed attackers to navigate and access all files on the server that were accessible to the PHP process, including files outside of the collections root or even outside of the Kirby installation. PHP code within such files was executed.

Such attacks first require an attack vector in the site code that is caused by dynamic collection names, such as `collection('tags-' . get('tags'))`. It generally also requires knowledge of the site structure and the server's file system by the attacker, although it can be possible to find vulnerable setups through automated methods such as fuzzing.

In a vulnerable setup, this could cause damage to the confidentiality and integrity of the server, for example:

- it could allow the attacker to build a map of the server's file system for subsequent attacks,
- it could allow access to configuration files that may contain sensitive information like security tokens or
- it could cause the unintended execution of PHP scripts.

Kirby CMS's `pages.access/list` and `files.access/list` permissions are not consistently checked in the Panel and REST API
### TL;DR

This vulnerability affects all Kirby sites where users of a particular role have no permission to access or list pages or files (`pages.access`, `pages.list`, `files.access` or `files.list` permission is disabled). This can be due to configuration in the user blueprint(s), via `options` in the model blueprint(s) or via a combination of both settings.

**This vulnerability is of high severity for affected sites.**

Consumers' Kirby sites are *not* affected if they intend all users to be able to access all pages and files of the site. The vulnerability can only be exploited by authenticated users. Write actions are *not* affected by this vulnerability.

----

### Introduction

Missing authorization allows authenticated users to perform actions they are not intended to have access to.

The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions.

Kirby provides the `pages.access`, `pages.list`, `files.access` and `files.list` permissions (among others). The `list` permissions control whether affected models appear in lists throughout the Panel and REST API. The `access` permissions have the same effect but also disable direct access to the affected models.

In affected releases, Kirby did not consistently hide non-listable models (models for which the respective `access` or `list` permission was disabled) in the following scenarios:

- The changes dialog in the Panel listed changed models even if they were not listable.
- The REST API respected the permissions during direct model access, but did not consistently filter collections as well as related models that are included in the API responses for convenience. This includes:
  - missing permission checks for children, drafts, files, parents and siblings of pages,
  - missing permission checks for parents and siblings (`next`/`nextWithTemplate `, `prev`/`prevWithTemplate`) of files,
  - missing permission checks for children, drafts and files of the site model,
  - missing permission checks for files of users,
  - incorrect permission checks for `pages.access` instead of `pages.list` for the site and pages children and search routes and
  - incorrect permission checks for `files.access` instead of `files.list` for the account, site, pages and users files and search routes,
- The Panel images for site, pages and users were displayed in lists of the parent model even if the image files were not listable.
- The link targets for the previous and next files in the files view were not gated by the files being listable.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, we have added permission checks for `$model->isListable()` in all of the affected places. This ensures that results are filtered by the listable property, thereby enforcing the `pages.access`, `pages.list`, `files.access` and `files.list` permissions consistently.

Kirby's page creation API bypasses the changeStatus permission check via unfiltered isDraft parameter
### TL;DR

This vulnerability affects all Kirby sites where users have the permission to create pages (`pages.create` permission is enabled) but not the permission to change the status of pages (`pages.changeStatus` permission is disabled). This can be due to configuration in the user blueprint(s), via `options` in the page blueprint(s) or via a combination of both settings.

Users' Kirby sites are *not* affected if their use case does not consider the creation of published pages a malicious action. The vulnerability can only be exploited by authenticated users.

----

### Introduction

An authorization bypass allows authenticated users to perform actions they should not be allowed to perform based on their configured permissions, thereby causing a privilege escalation.

The effects of an authorization bypass can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions.

For pages, Kirby provides the `pages.create` and `pages.changeStatus` permissions (among others). In affected releases, Kirby checked these permissions independently and only for the respective action. However the `changeStatus` permission didn't take effect on page creation.

New pages are created as drafts by default and need to be published by changing the page status of an existing page draft. This is ensured when the page is created via the Kirby Panel. However the REST API allows to override the `isDraft` flag when creating a new page. This allowed authenticated attackers with the `pages.create` permission to immediately create published pages, bypassing the normal editorial workflow.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, Kirby has added a check to the page creation rules that ensures that users without the `pages.changeStatus` permission cannot create published pages, only page drafts.

### Credits

Kirby thanks @offset for responsibly reporting the identified issue.

Kirby CMS's system API endpoint leaks installed version and license data to authenticated users
### TL;DR

This vulnerability affects all Kirby sites that might have potential attackers in the group of authenticated Panel users.

----

### Introduction

Missing authorization allows authenticated users to perform actions they are not intended to have access to.

The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). The permissions control the authorization of user actions (with handling of model-specific authorization omitted here for brevity).

Kirby provides the `access.system` permission (among others) that controls access to the system area of the Kirby Panel. This area contains internal system information like the installed Kirby, plugin and server versions, security state and Kirby license. If the `access.system` permission is disabled for a user role, users of that role should not be able to access this internal system information. However it is also possible to access some system information via the `/api/system` REST API endpoint. In affected releases, the response of this endpoint for authenticated users contained the installed Kirby version and the status, type and code of the installed Kirby license. These values are considered sensitive information and should be protected by the `access.system` permission.

The installed Kirby version and license data can be used by malicious actors during reconnaissance when planning a separate attack.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, we have protected the version and license properties of the `/api/system` endpoint with a check for the existing `access.system` permission. This ensures that the REST API only outputs information that should be accessible to the user via the Panel.

### Credits

Kirby thanks @HuajiHD and @0x-bala for responsibly reporting the identified issue.

Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering
### TL;DR

This vulnerability affects all Kirby sites that use option fields (`checkboxes`, `color`, `multiselect`, `select`, `radio`, `tags` or `toggles`) with options from a query or API whose values may not be fully trusted. It also affects direct uses of the `OptionsApi` or `OptionsQuery` classes of Kirby's `Options` package from plugin or site code. The attack requires either an attacker in the group of authenticated Panel users or user interaction of another authenticated user.

**This vulnerability is of high severity for affected sites.**

Users' Kirby sites are *not* affected if they are not using any of the mentioned fields or the `Options` package, if all options are defined statically in the blueprints or if all dynamically gathered options are to be trusted.

----

### Introduction

Server-Side Template Injection vulnerabilities (SSTI) occur when user input is embedded in a template in an unsafe manner and results in remote code execution on the server.

Injected user input is wrongly treated as a template command instead of as a literal string of text. This allows attackers to query arbitrary information from the affected system or call arbitrary methods to perform actions.

In a Kirby site this can be used to access protected site information, alter site content or break site behavior.

### Impact

Kirby provides field types (`checkboxes`, `color`, `multiselect`, `select`, `radio`, `tags` and `toggles`) that offer a fixed set of options from a configured list. This configured list can be statically defined in the blueprint or it can come from a Kirby query or (external) API source. Options coming from a query or API are treated as dynamic.

Static options can contain queries in the form `{{ query }}` or `{< query >}` that are then evaluated to a static value. Because the queries are defined in the blueprint, they can be trusted and cannot be controlled by attackers.

However, dynamic options can often not be trusted. This is why the "options from query" and "options from API" modes are intended to resolve the option values and text strings based on queries not defined within the data source but within the blueprint.

Unfortunately, the results of these trusted queries on untrusted source data are run through the query parser a second time in affected Kirby releases.

Because of the double-resolution of dynamic option values and text strings, attackers could place malicious query templates such as `{{ users.first.password }}` or `{{ page.delete }}` in the option sources such as page titles or external API data controlled by the attacker. These queries would then be executed when the field is loaded in the Panel. When the attacker directly accesses the respective Panel view, they could get access to information normally hidden from them. As the malicious query templates are loaded for all users, it could also lead to malicious write access when another user with a higher permission level accesses the manipulated Panel view.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, Kirby has updated the `Options` logic to no longer double-resolve queries in option values coming from `OptionsQuery` or `OptionsApi` sources. Kirby now only resolves queries that are directly configured in the blueprints.

### Credits

Kirby thanks to @offset for responsibly reporting the identified issue.

Incorrect Authorization
Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites that might have potential attackers in the group of authenticated Panel users or that allow external visitors to update a Kirby content file (e.g. via a contact or comment form). Kirby sites are *not* affected if they don't allow write access for untrusted users or visitors.

A field injection in a content storage implementation is a type of vulnerability that allows attackers with content write access to overwrite content fields that the site developer didn't intend to be modified. In a Kirby site this can be used to alter site content, break site behavior or inject malicious data or code. The exact security risk depends on the field type and usage.

Kirby stores content of the site, of pages, files and users in text files by default. The text files use Kirby's KirbyData format where each field is separated by newlines and a line with four dashes (`----`). When reading a KirbyData file, the affected code first removed the Unicode BOM sequence from the file contents and afterwards split the content into fields by the field separator.

When writing to a KirbyData file, field separators in field data are escaped to prevent user input from interfering with the field structure. However this escaping could be tricked by including a Unicode BOM sequence in a field separator (e.g. `--\xEF\xBB\xBF--`). When writing, this was not detected as a separator, but because the BOM was removed during reading, it could be abused by attackers to inject other field data into content files.

Because each field can only be defined once per content file, this vulnerability only affects fields in the content file that were defined above the vulnerable user-writable field or not at all. Fields that are defined below the vulnerable field override the injected field content and were therefore already protected.

The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have fixed the affected code to only remove the Unicode BOM sequence at the beginning of the file. This fixes this vulnerability both for newly written as well as for existing content files.

Kirby CMS doesn't gate user avatar creation, replacement and deletion with user update permissions
### TL;DR

This vulnerability affects all Kirby sites where users of a particular role have no permission to update user information (`user.update` or `users.update` permission is disabled). This can be due to configuration in the blueprint(s) of the acting users, via `options` in the blueprint(s) of the target users or via a combination of both settings.

Kirby sites are *not* affected if they intend all users of the site to be able to upload, replace or delete user avatars. The vulnerability can only be exploited by authenticated users.

----

### Introduction

Missing authorization allows authenticated users to perform actions they are not intended to have access to.

The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model using the `options` feature (for user models again in the user blueprints). The permissions and options together control the authorization of user actions.

Kirby provides the `user.update` and `users.update` permissions (among others) that control the authorization to update user information for the user's own data or the data of other users respectively. User files are separately gated by the `files.create`, `files.replace` and `files.delete` permissions (among others).

In affected releases, Kirby only checked the `files.create` and `files.delete` permissions during changes to user avatars. Even though avatars are an integral part of the user profile, they were not covered by the `user.update` and `users.update` permissions. This allowed users with just file permissions to create, replace or delete user avatars.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, we have added additional permission checks for `user.update`/`users.update` when a user avatar is created, replaced or deleted. These permission checks apply in addition to the file permission checks (`files.create`, `files.replace` and `files.delete`). When a user avatar is replaced with a file of the same type, Kirby now consistently checks the `files.replace` permission instead of a combination of `files.create` and `files.delete`.

Kirby CMS's read access to site, user and role information is not gated by permissions
### TL;DR

This vulnerability affects all Kirby sites that might have potential attackers in the group of authenticated Panel users.

**This vulnerability is of high severity for affected sites.**

Sites using Kirby are *not* affected if they intend all users of the site to be able to list and access the site model and all users and roles, including the content stored within these models. Write actions are *not* affected by this vulnerability as they were gated by permissions before.

----

### Introduction

Missing authorization allows authenticated users to perform actions they are not intended to have access to.

The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions.

In affected releases, Kirby did not provide permission settings that control the access to the site model as well as to users and user roles. If the site developer disabled all permissions via the wildcard `"*": false` setting, this only disabled the actions that were explicitly gated by existing permissions.

To be specific, the following permissions were missing in affected releases and have been added in the patches:

- `site.access`
- `user.access` and `users.access` (for the own user and other users respectively)
- `user.list` and `users.list` (for the own user and other users respectively)

Access to role information such as the list of existing roles, their names and descriptions as well as their configured permissions were also not gated by user-based permissions.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, Kirby has added the missing permissions that are listed in the "Impact" section. The `user.access` and `users.access` permissions also take effect on the access to the user's own role and to other roles respectively.

### Credits

Kirby thanks @HuajiHD for responsibly reporting the identified issue.

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites that might have potential attackers in the group of authenticated Panel users or that allow external visitors to upload an arbitrary file to the content folder. Kirby sites are not affected if they don't allow file uploads for untrusted users or visitors or if the file extensions of uploaded files are limited to a fixed safe list. The attack requires user interaction by another user or visitor and cannot be automated.

An editor with write access to the Kirby Panel could upload a file with an unknown file extension like `.xyz` that contains HTML code including harmful content like `<script>` tags. The direct link to that file could be sent to other users or visitors of the site. If the victim opened that link in a browser where they are logged in to Kirby and the file had not been opened by anyone since the upload, Kirby would not be able to send the correct MIME content type, instead falling back to `text/html`. The browser would then run the script, which could for example trigger requests to Kirby's API with the permissions of the victim.

The issue was caused by the underlying `Kirby\Http\Response::file()` method, which didn't have an explicit fallback if the MIME type could not be determined from the file extension. If you use this method in site or plugin code, these uses may be affected by the same vulnerability.

The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have fixed the affected method to use a fallback MIME type of `text/plain` and set the `X-Content-Type-Options: nosniff` header if the MIME type of the file is unknown.

Kirby is vulnerable to authorization bypass during page, file and user creation via blueprint injection
### TL;DR

This vulnerability affects all Kirby sites where users of a particular role have no permission to create pages, files or users (`pages.create`, `files.create` or `users.create` permission is disabled). This can be due to configuration in the user blueprint(s), via `options` in the model blueprint(s) or via a combination of both settings.

**This vulnerability is of high severity for affected sites.**

Developers' Kirby sites are *not* affected if they intend all users of their site to be able to create pages, files and users. The vulnerability can only be exploited by authenticated users.

----

### Introduction

An authorization bypass allows authenticated users to perform actions they should not be allowed to perform based on their configured permissions, thereby causing a privilege escalation.

The effects of an authorization bypass can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions.

Kirby provides the `pages.create`, `files.create` and `users.create` permissions (among others). These permissions can again be set in the user blueprint and/or in the blueprint of the target model via `options`. In affected releases, Kirby allowed to override the `options` during the creation of pages, files and users by injecting custom dynamic blueprint configuration into the model data. The injected `options` could include `'create' => true`, which then caused an override of the permissions and options configured by the site developer in the user and model blueprints.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, we have updated the normalization code that is used during the creation of pages, files and users to include a filter for the `blueprint` property. This prevents the injection of dynamic blueprint configuration into the creation request.

### Credits

Kirby thanks @offset for responsibly reporting the identified issue.

Kirby has XML injection in its XML creator toolkit
### TL;DR

This vulnerability only affects Kirby sites that use the `Xml` data handler (e.g. `Data::encode($string, 'xml')`) or the `Xml::create()`, `Xml::tag()` or `Xml::value()` method(s) in site or plugin code. The Kirby core does not use any of the affected methods.

If consumers use an affected method and cannot rule out input to these methods controlled by an attacker, Kirby strongly recommends that they update to a patch release.

----

### Introduction

XML strings contain structured data in tags and attributes. Depending on the used XML schema, this data can carry specific meaning that can lead to actions in other systems that parse and act on the XML data. Tags and attributes are detected based on their specific syntax, which includes characters such as `<`, `>`, `"`, and `&`. If these characters are to be used verbatim in text within the XML string, they can be escaped using a `<![CDATA[ ]]>` block.

XML injection is an attack on a system generating or parsing XML files. By injecting special characters into input data, XML output with a malicious meaning could be generated by a vulnerable system.

### Impact

Kirby's `Xml::value()` method has special handling for `<![CDATA[ ]]>` blocks. If the input value is already valid `CDATA`, it is not escaped a second time but allowed to pass through. However it was possible to trick this check into allowing values that only *contained* a valid `CDATA` block but also contained other structured data outside of the `CDATA` block. This structured data would then also be allowed to pass through, circumventing the value protection.

The `Xml::value()` method is used in `Xml::tag()`, `Xml::create()` and in the `Xml` data handler (e.g. `Data::encode($string, 'xml')`).

Both the vulnerable methods and the data handler are not used in the Kirby core. However they may be used in site or plugin code, e.g. to create XML strings from input data. If those generated files are passed to another implementation that assigns specific meaning to the XML schema, manipulation of this system's behavior is possible.

Kirby sites that don't use XML generation in site or plugin code are *not* affected.

### Patches

The problem has been patched in [Kirby 4.9.0](https://github.com/getkirby/kirby/releases/tag/4.9.0) and [Kirby 5.4.0](https://github.com/getkirby/kirby/releases/tag/5.4.0). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.

In all of the mentioned releases, Kirby has added additional checks that only allow unchanged `CDATA` passthrough if the entire string is made up of valid `CDATA` blocks and no structured data. This protects all uses of the method against the described vulnerability.

### Credits

Kirby thanks to Patrick Falb (@dapatrese) at [FORMER 03](https://former03.de/) for responsibly reporting the identified issue.

Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with user accounts (unless Kirby's API and Panel are disabled in the config). It can only be abused if a Kirby user is logged in on a device or browser that is shared with potentially untrusted users or if an attacker already maliciously used a previous password to log in to a Kirby site as the affected user.

Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization. In the variation described in this advisory, it allows attackers to stay logged in to a Kirby site on another device even if the logged in user has since changed their password. Kirby does not invalidate user sessions that were created with a password that was since changed by the user or by a site admin. If a user changed their password to lock out an attacker who was already in possession of the previous password or of a login session on another device or browser, the attacker would not be reliably prevented from accessing the Kirby site as the affected user.

The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have updated the authentication implementation to keep track of the hashed password in each active session. If the password changed since the login, the session is invalidated. To enforce this fix even if the vulnerability was previously abused, all users are logged out from the Kirby site after updating to one of the patched releases.