Executive brief
TYPO3 CMS, a popular content management system, contains a security flaw in how it handles stored data in its cache and registry components. An attacker who already has local access to the server's database or file system could use this flaw to execute malicious code, potentially leading to a full system takeover. This vulnerability could result in significant data breaches or complete service disruption if an attacker gains a foothold on the hosting environment.
Technical details
The vulnerability exists in TYPO3's cache frontend (VariableFrontend) and persistent key-value store (Registry), which deserialize PHP payloads without proper integrity validation or class restrictions. This root cause allows for PHP Object Injection (CWE-502). To exploit this, an attacker must have existing local write access to the underlying storage backend, such as the SQL database (sys_registry table) or the file system's cache store. By injecting a crafted serialized payload, an attacker can leverage available gadget chains to achieve Remote Code Execution (RCE). Patches are available in versions 10.4.57 ELTS, 11.5.51 ELTS, 12.4.46 ELTS, 13.4.31 LTS, and 14.3.3 LTS.
Affected products
- TYPO3 TYPO3 CMS < 10.4.57, 11.0.0-11.5.50, 12.0.0-12.4.45, 13.0.0-13.4.30, 14.0.0-14.3.2
Timeline
- 2026-06-09: disclosed
- 2026-06-09: advisory: TYPO3-CORE-SA-2026-018 published
- 2026-06-12: patched
References
- https://github.com/TYPO3/typo3/security/advisories/GHSA-c78m-c52x-jgwp
- https://github.com/TYPO3/typo3/commit/48bcf24f31f52cc0b43d3bea4984634bd2cf85c7
- https://github.com/TYPO3/typo3/commit/87cd7c5b710c44d3606fed277b040a75dc6a9c02
- https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-49740.yaml
- https://typo3.org/security/advisory/typo3-core-sa-2026-018