Summary
TYPO3 CMS Possible Insecure Deserialization in Extbase Request Handling
It has been discovered that request handling in Extbase can be vulnerable to insecure deserialization. User submitted payload has to be signed with a corresponding HMAC-SHA1 using the sensitive TYPO3 encryptionKey as secret - invalid or unsigned payload is not deserialized.
However, since sensitive information could have been leaked by accident (e.g. in repositories or in commonly known and unprotected backup files), there is the possibility that attackers know the private encryptionKey and are able to calculate the required HMAC-SHA1 to allow a malicious payload to be deserialized.
Requirements for successfully exploiting this vulnerability (all of the following):
- rendering at least one Extbase plugin in the frontend
- encryptionKey has been leaked (from LocalConfiguration.php or corresponding .env file)
Impact
GHSA-HH95-5XM5-V8V7 has a CVSS score of 8.1 (High). The vector is network-reachable, no 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 (8.7.30, 9.5.12); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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typo3/cms to 8.7.30 or later; typo3/cms to 9.5.12 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-HH95-5XM5-V8V7? GHSA-HH95-5XM5-V8V7 is a high-severity security vulnerability in typo3/cms (composer), affecting versions >= 8.0.0, < 8.7.30. It is fixed in 8.7.30, 9.5.12.
- How severe is GHSA-HH95-5XM5-V8V7? GHSA-HH95-5XM5-V8V7 has a CVSS score of 8.1 (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.
- Which versions of typo3/cms are affected by GHSA-HH95-5XM5-V8V7? typo3/cms (composer) versions >= 8.0.0, < 8.7.30 is affected.
- Is there a fix for GHSA-HH95-5XM5-V8V7? Yes. GHSA-HH95-5XM5-V8V7 is fixed in 8.7.30, 9.5.12. Upgrade to this version or later.
- Is GHSA-HH95-5XM5-V8V7 exploitable, and should I be worried? Whether GHSA-HH95-5XM5-V8V7 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
- What actually determines whether GHSA-HH95-5XM5-V8V7 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.
- How do I fix GHSA-HH95-5XM5-V8V7?
- Upgrade
typo3/cmsto 8.7.30 or later - Upgrade
typo3/cmsto 9.5.12 or later
- Upgrade