Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / packagist/typo3/cms/CVE-2021-21355
Advisory ID gitlab/packagist/typo3/cms/CVE-2021-21355
Aliases CVE-2021-21355
GHSA-2r6j-862c-m2v2
Summary Unrestricted Upload of File with Dangerous Type Due to the lack of ensuring file extensions belong to configured allowed mime-types, attackers can upload arbitrary data with arbitrary file extensions - however, default `_fileDenyPattern_` successfully blocked files like `_.htaccess_` or `_malicious.php_`. Additionally, `_UploadedFileReferenceConverter_` transforming uploaded files into proper FileReference domain model objects handles possible file uploads for other extensions as well - given those extensions use the Extbase MVC framework, make use of FileReference items in their direct or inherited domain model definitions and did not implement their own type converter. In case this scenario applies, `_UploadedFileReferenceConverter_` accepts any file mime-type and persists files in the default location. In any way, uploaded files are placed in the default location `_/fileadmin/user_upload/_`, in most scenarios keeping the submitted filename - which allows attackers to directly reference files, or even correctly guess filenames used by other individuals, disclosing this information. No authentication is required to exploit this vulnerability.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (4)
CWE-434 Unrestricted Upload of File with Dangerous Type
CWE-552 Files or Directories Accessible to External Parties
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv2 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/typo3/cms/CVE-2021-21355.yml
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/typo3/cms/CVE-2021-21355.yml
Reference id Reference type URL
https://typo3.org/security/advisory/typo3-core-sa-2021-002
CVE-2021-21355 https://nvd.nist.gov/vuln/detail/CVE-2021-21355
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/typo3/cms/CVE-2021-21355.yml
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/typo3/cms/CVE-2021-21355.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.