CVE-2026-107845

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 Unpublished comments remain visible to moderators, so moderation does not prevent exposure.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.

CVSS v3 9.3 CRITICAL

9.3^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 2.8 / Impact : 5.8

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope CHANGED

References

Link	Resource
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/contao/contao/security/advisories/GHSA-628f-v4f6-p37r

Configurations

No configuration.

History

09 Oct 2026, 20:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-09 20:17

Updated : 2026-10-16 17:17

NVD link : CVE-2026-107845

Mitre link : CVE-2026-107845

CVE.ORG link : CVE-2026-107845

JSON object : View

Products Affected

No product.

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CWE-116

Improper Encoding or Escaping of Output

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