CVE-2026-107845
Published:October 09, 2026
Updated:October 13, 2026
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 Unpublished comments remain visible to moderators, so moderation does not prevent exposure.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
https://github.com/contao/contao.git (GITHUB):
Affected version(s) >=5.4.0-RC1 <5.7.12Fix Suggestion:
Update to version 5.7.12https://github.com/contao/contao.git (GITHUB):
Affected version(s) >=4.0.0 <5.3.50Fix Suggestion:
Update to version 5.3.50contao/comments-bundle (PHP):
Affected version(s) >=4.0.0 <5.3.50Fix Suggestion:
Update to version 5.3.50contao/comments-bundle (PHP):
Affected version(s) >=5.4.0-RC1 <5.7.12Fix Suggestion:
Update to version 5.7.12Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
EPSS
Base Score:
0.27