Component Type: TYPO3 CMSSubcomponent: Core API (ext:core)Release Date: June 9, 2026Vulnerability Type: Insecure DeserializationAffected Versions: 10.0.0-10.4.56, 11.0.0-11.5.50, 12.0.0-12.4.45, 13.0.0-13.4.30, 14.0.0-14.3.2Severity: MediumSuggested CVSS: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:HReferences: CVE-2026-49740, CWE-502 Problem Description TYPO3's cache frontend (VariableFrontend) and persistent key-value store (Registry) deserialized PHP payloads without integrity validation or class restrictions. An attacker with write access to the underlying storage backend (cache store or sys_registry database table) could inject a crafted serialized payload to trigger PHP Object Injection, potentially exploiting a gadget chain to achieve Remote Code Execution or other high-impact effects. Exploiting this vulnerability requires direct local write access to the storage, such as the SQL database or file system. Solution Update to TYPO3 versions 10.4.57 ELTS, 11.5.51 ELTS, 12.4.46 ELTS, 13.4.31 LTS, 14.3.3 LTS that fix the problem described. Credits Thanks to “z3rco”, Chowdhury Faizal Ahammed, Rick Larabee, Vitaly Simonovich, Nozomu Sasaki, Mert Akdag, “tikket”, Shafi Almutairi for reporting this issue, and to TYPO3 core & security team member Oliver Hader for fixing it. General Advice Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list. General Note All security-related code changes are tagged so you can easily look them up in our review system.