- Component Type: TYPO3 CMS
- Vulnerable subcomponent: File List (ext:filelist)
- Release Date: January 22, 2019
- Vulnerability Type: Arbitrary Code Execution
- Affected Versions: 8.0.0-8.7.22 and 9.0.0-9.5.3
- Severity: None - Critical (depending on web server configuration)
- Suggested CVSS v3.0: AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C
- CVE: not assigned yet
Due to missing file extensions in $GLOBALS['TYPO3_CONF_VARS']['BE'][‘fileDenyPattern’], backend users are allowed to upload *.phar, *.shtml, *.pl or *.cgi files which can be executed in certain web server setups. A valid backend user account is needed in order to exploit this vulnerability.
Derivatives of Debian GNU Linux are handling *.phar files as PHP applications since PHP 7.1 (for unofficial packages) and PHP 7.2 (for official packages).
The file extension *.shtml is bound to server side includes which are not enabled per default in most common Linux based distributions. File extension *.pl and *.cgi require additional handlers to be configured which is also not the case in most common distributions (except for /cgi-bin/ location).
Update to TYPO3 versions 8.7.23 or 9.5.4 to fix the problem described.
Thanks to Edgar Boda-Majer and Lauritz Holtmann who reported these issues and to TYPO3 core team member Oliver Hader who fixed the issue.
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