critical9.3
CVE-2026-107845
Contao: Cross-site scripting in the comments bundle
Impact
Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, an unauthenticated visitor can submit a comment whose email or website metadata is rendered without sufficient attribute and URL encoding by listComments() in comments-bundle/contao/dca/tl_comments.php. When a backend user opens the Comments module, attacker-controlled script can execute in the Contao backend origin under that user's session. Unpublished comments remain visible to moderators, so moderation does not prevent exposure. This issue is fixed in versions 5.3.50 and 5.7.12.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | contao/comments-bundle | >= 4.0.0, < 5.3.50 | 5.3.50 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-628f-v4f6-p37r
- https://github.com/contao/contao/security/advisories/GHSA-628f-v4f6-p37r
- https://github.com/contao/contao/commit/22505d5f79bc1a7f52e2cba5fddf6007e1f0408a
- https://github.com/contao/contao/releases/tag/5.3.50
- https://github.com/contao/contao/releases/tag/5.7.12