Vulnerability · Published Oct 9, 2026 · Assigned by GitHub_M

CVE-2026-107848Contao: Cross-site request forgery in custom backend actions

Low 3.5

In plain English

A low-severity cross-site request forgery in contao from contao. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.5Low

Exploit odds (30 days)0.1%top 98.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, RequestTokenListener validates REQUEST_TOKEN only for POST requests, while the declarative GET guard runs only when an act parameter is present. Backend actions dispatched through the key parameter can therefore execute without a CSRF token when an authenticated backend user loads an attacker-controlled URL. Reachable actions remain limited to modules available to that user, and the advisory demonstrates destructive or state-changing actions rather than privilege escalation. This issue is fixed in versions 5.3.50 and 5.7.12.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	contao/core-bundle	5.3.50	GHSA-9ff2-p842-45wq
Packagist	contao/core-bundle	5.7.12	GHSA-9ff2-p842-45wq

Affected products (as reported)

Vendor	Product	Versions
contao	contao	>= 4.0.0, < 5.3.50>= 5.4.0-RC1, < 5.7.12

Weakness: CWE-352 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

References

https://github.com/contao/contao/security/advisories/GHSA-9ff2-p842-45wq x_refsource_CONFIRM
https://github.com/contao/contao/commit/34dd27ee6739f10568d3d95d8784862255c925b4 x_refsource_MISC
https://github.com/contao/contao/releases/tag/5.7.12 x_refsource_MISC