# CVE-2026-49740: TYPO3 CMS insecure deserialization in VariableFrontend and Registry

Source: https://junglewise.ai/threats/cve-2026-49740-typo3-cms-insecure-deserialization-in-variablefrontend-and  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-12  
License: CC BY 4.0 with a link back

CVE-2026-49740 · Severity: medium · CVSS 4 · Published 2026-06-09

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.

Technologies: [typo3/cms-core (Packagist)](https://junglewise.ai/threats/technologies/typo3-cms-core). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-49740 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-49740 being exploited in the wild.

**How severe is CVE-2026-49740?** Medium severity, with a CVSS score of 4, published 9 June 2026.

**Which products and versions are affected?** typo3/cms-core (Packagist) ECOSYSTEM:introduced=0,fixed=10.4.57.

**Is there a fix for CVE-2026-49740?** Yes. typo3/cms-core (Packagist): upgrade to 10.4.57 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-49740 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-49740?** Check whether you run typo3/cms-core (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- typo3/cms-core (Packagist): upgrade to 10.4.57 or later

  ```sh
  composer require typo3/cms-core:^10.4.57
  ```


## 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

## Identifiers

- CVE-2026-49740
- GHSA-c78m-c52x-jgwp

## 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/security/advisories/GHSA-c78m-c52x-jgwp)
- [https://github.com/TYPO3/typo3/commit/48bcf24f31f52cc0b43d3bea4984634bd2cf85c7](https://github.com/TYPO3/typo3/commit/48bcf24f31f52cc0b43d3bea4984634bd2cf85c7)
- [https://github.com/TYPO3/typo3/commit/87cd7c5b710c44d3606fed277b040a75dc6a9c02](https://github.com/TYPO3/typo3/commit/87cd7c5b710c44d3606fed277b040a75dc6a9c02)
- [https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-49740.yaml](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](https://typo3.org/security/advisory/typo3-core-sa-2026-018)

## Related threats

- [The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 became ineffective in TYPO3 v13.0, where TYPO3 CMS started](https://junglewise.ai/threats/cve-2026-19418-typo3-cms-broken-access-control-in-backend-and-install-tool)
- [TYPO3 CMS broken access control in Media Module](https://junglewise.ai/threats/cve-2026-49742-typo3-cms-broken-access-control-in-media-module)
- [TYPO3 CMS broken access control in Form Framework form_definition table](https://junglewise.ai/threats/cve-2026-49741-typo3-cms-broken-access-control-in-form-framework-form-definition)
- [TYPO3 CMS path traversal in GeneralUtility::isAllowedAbsPath](https://junglewise.ai/threats/cve-2026-49738-typo3-cms-path-traversal-in-generalutility-isallowedabspath)
- [TYPO3 CMS broken access control in Backend API](https://junglewise.ai/threats/cve-2026-47352-typo3-cms-broken-access-control-in-backend-api)