Summary
Insecure Deserialization in TYPO3 CMS
It has been discovered that the Form Framework (system extension "form") is vulnerable to Insecure Deserialization when being used with the additional PHP PECL package “yaml”, which is capable of unserializing YAML contents to PHP objects. A valid backend user account as well as having PHP setting "yaml.decode_php" enabled is needed to exploit this vulnerability (which is the default value according to PHP documentation).
Impact
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
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 8.7.17 or later; typo3/cms to 9.3.2 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-8H28-F46F-M87H? GHSA-8H28-F46F-M87H is a high-severity insecure deserialization vulnerability in typo3/cms (composer), affecting versions >= 8.5.0, < 8.7.17. It is fixed in 8.7.17, 9.3.2. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- Which versions of typo3/cms are affected by GHSA-8H28-F46F-M87H? typo3/cms (composer) versions >= 8.5.0, < 8.7.17 is affected.
- Is there a fix for GHSA-8H28-F46F-M87H? Yes. GHSA-8H28-F46F-M87H is fixed in 8.7.17, 9.3.2. Upgrade to this version or later.
- Is GHSA-8H28-F46F-M87H exploitable, and should I be worried? Whether GHSA-8H28-F46F-M87H 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-8H28-F46F-M87H 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-8H28-F46F-M87H?
- Upgrade
typo3/cmsto 8.7.17 or later - Upgrade
typo3/cmsto 9.3.2 or later
- Upgrade