Contao: Cross-site request forgery in custom backend actions

[ Description ]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.

[ Fixes ]Fixes and patches

• contao/core-bundle 5.3.50Fixed version · GitHub Advisories · composer package contao/core-bundle: upgrade to 5.3.50 or later (affected >= 4.0.0, < 5.3.50)
• contao/core-bundle 5.7.12Fixed version · GitHub Advisories · composer package contao/core-bundle: upgrade to 5.7.12 or later (affected >= 5.4.0-RC1, < 5.7.12)

[ Packages ]Affected open-source packages

• contao/core-bundle composerAffected >= 4.0.0, < 5.3.50 · fixed in 5.3.50 · GHSA-9ff2-p842-45wq
• contao/core-bundle composerAffected >= 5.4.0-RC1, < 5.7.12 · fixed in 5.7.12 · GHSA-9ff2-p842-45wq

[ References ]References

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