CVE-2026-107845
Severity CVSS v4.0:
Pending analysis
Type:
CWE-79
Cross-Site Scripting (XSS)
Publication date:
09/10/2026
Last modified:
09/10/2026
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 Unpublished comments remain visible to moderators, so moderation does not prevent exposure.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.
Impact
Base Score 3.x
9.30
Severity 3.x
CRITICAL