CVE-2026-107845 · GHSA-628f-v4f6-p37r
Contao: Cross-site scripting in the comments bundle
- Risk score
- 70/100
- CVSS
- 9.3 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 9 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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 mod…
- Affected
- contao/comments-bundle (composer) >= 4.0.0, < 5.3.50; contao/comments-bundle (composer) >= 5.4.0-RC1, < 5.7.12
- Fix
- Upgrade contao/comments-bundle to 5.3.50 or 5.7.12 (whichever matches your release line) or later.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 9.3 critical
- Remotely exploitable without logging in
- On your watchlist: Composer
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| contao/comments-bundle | composer | >= 4.0.0, < 5.3.50 | 5.3.50 |
| contao/comments-bundle | composer | >= 5.4.0-RC1, < 5.7.12 | 5.7.12 |
References
- 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
- https://github.com/advisories/GHSA-628f-v4f6-p37r
Original description
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 Unpublished comments remain visible to moderators, so moderation does not prevent exposure.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.
Last activity 9 Oct 2026. Patch Forecast updates every hour.