CVE-2026-49740: TYPO3 CMS - Insecure Deserialization in Core API
Problem 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 sysregistry 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 TYPO3 CMS thanks “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.
Resources TYPO3-CORE-SA-2026-018
Other sources
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 sysregistry 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. This issue affects TYPO3 CMS versions before 10.4.57, 11.0.0-11.5.50, 12.0.0-12.4.45, 13.0.0-13.4.30 and 14.0.0-14.3.2.
— MITRE
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 sysregistry 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. This issue affects TYPO3 CMS versions before 10.4.57, 11.0.0-11.5.51, 12.0.0-12.4.46, 13.0.0-13.4.31 and 14.0.0-14.3.3.
— NVD
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 14.3.3 - Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 13.4.31 - Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 12.4.46 - Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 11.5.51 - Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 10.4.57 - Upgrade
Upgrade
TYPO3 CMSto a version that resolves this vulnerability.Fixed in 10.4.57 ELTS - Upgrade
Upgrade
TYPO3 CMSto a version that resolves this vulnerability.Fixed in 11.5.51 ELTS - Upgrade
Upgrade
TYPO3 CMSto a version that resolves this vulnerability.Fixed in 12.4.46 ELTS - Upgrade
Upgrade
TYPO3 CMSto a version that resolves this vulnerability.Fixed in 13.4.31 LTS - Upgrade
Upgrade
TYPO3 CMSto a version that resolves this vulnerability.Fixed in 14.3.3 LTS - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch TYPO3-CORE-SA-2026-018
Event History
Frequently Asked Questions
What is the severity of CVE-2026-49740?
CVE-2026-49740 has a medium severity rating of 6.3 according to the CVSS score.
How do I fix CVE-2026-49740?
To fix CVE-2026-49740, ensure that you update TYPO3 CMS to the latest version where the vulnerability has been addressed.
What are the implications of CVE-2026-49740?
CVE-2026-49740 allows an attacker with write access to exploit insecure deserialization in TYPO3's cache frontend and key-value store.
Which TYPO3 versions are affected by CVE-2026-49740?
CVE-2026-49740 affects all versions of TYPO3 CMS that utilize the insecure deserialization in the core API.
Is there a known exploit for CVE-2026-49740?
As of now, there is no public knowledge of active exploits specifically targeting CVE-2026-49740.