Package Instance

Files uploaded by anonymous users accessed by other users
Private files that have been uploaded by an anonymous user but not permanently attached to content on the site should only be visible to the anonymous user that uploaded them, rather than all anonymous users. Drupal core does not provide this protection, allowing an access bypass vulnerability to occur. This issue is mitigated by the fact that in order to be affected, the site must allow anonymous users to upload files into a private file system.

Comment reply form allows access to restricted content
Users with permission to post comments are able to view content and comments they do not have access to, and are also able to add comments to this content. This vulnerability is mitigated by the fact that the comment system must be enabled and the attacker must have permission to post comments.

Cross-site Scripting in HTTP exceptions
An attacker can create a specially crafted url, which can execute arbitrary code in the victim’s browser if loaded. Drupal is not properly sanitizing an exception.

Cross-site Scripting
In Symfony, validation messages are not escaped, which can lead to XSS when user input is included.

Language fallback can be incorrect on multilingual sites with node access restrictions
When using node access controls with a multilingual site, Drupal marks the untranslated version of a node as the default fallback for access queries. This fallback is used for languages that do not yet have a translated version of the created node. This can result in an access bypass vulnerability. This issue is mitigated by the fact that it only applies to sites that a) use the Content Translation module; and b) use a node access module such as Domain Access which implement hook_node_access_records(). Note that the update will mark the node access tables as needing a rebuild, which will take a long time on sites with a large number of nodes.

PECL YAML parser unsafe object handling
PECL YAML parser does not handle PHP objects safely during certain operations within Drupal core. This can lead to remote code execution.

JavaScript cross-site scripting prevention is incomplete
Drupal has a Drupal.checkPlain() JavaScript function which is used to escape potentially dangerous text before outputting it to HTML (as JavaScript output is not auto-escaped by either Drupal 7 or Drupal 8). This function does not correctly handle all methods of injecting malicious HTML, leading to a cross-site scripting vulnerability under certain circumstances. The PHP functions which Drupal provides for HTML escaping are not affected.

File REST resource does not properly validate
The file REST resource does not properly validate some fields when manipulating files. the file REST resource is enabled and allows PATCH requests, and an attacker can get or register a user account on the site with permissions to upload files and to modify the file resource.