GHSA-F9HR-7CFQ-MJG2

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).

The application accepts file uploads without adequately restricting the file type or content. Typical impact: remote code execution if the uploaded file can be served and executed on the server.

GHSA-F9HR-7CFQ-MJG2 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (8.7.23, 9.5.4); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is GHSA-F9HR-7CFQ-MJG2? GHSA-F9HR-7CFQ-MJG2 is a high-severity unrestricted upload of dangerous file types vulnerability in typo3/cms-core (composer), affecting versions >= 8.0.0, < 8.7.23. It is fixed in 8.7.23, 9.5.4. The application accepts file uploads without adequately restricting the file type or content.
2. How severe is GHSA-F9HR-7CFQ-MJG2? GHSA-F9HR-7CFQ-MJG2 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of typo3/cms-core are affected by GHSA-F9HR-7CFQ-MJG2? typo3/cms-core (composer) versions >= 8.0.0, < 8.7.23 is affected.
4. Is there a fix for GHSA-F9HR-7CFQ-MJG2? Yes. GHSA-F9HR-7CFQ-MJG2 is fixed in 8.7.23, 9.5.4. Upgrade to this version or later.
5. Is GHSA-F9HR-7CFQ-MJG2 exploitable, and should I be worried? Whether GHSA-F9HR-7CFQ-MJG2 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-F9HR-7CFQ-MJG2 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-F9HR-7CFQ-MJG2?
   • Upgrade typo3/cms-core to 8.7.23 or later
   • Upgrade typo3/cms-core to 9.5.4 or later

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