CVE-2026-107845

Received
Published: 09 Oct 2026, 19:29
Last modified:09 Oct 2026, 19:51

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.3 CRITICAL
v3.1 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

09 Oct 2026, 19:29
Published
Vulnerability first disclosed
09 Oct 2026, 19:51
Last Modified
Vulnerability information updated

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 Unpublished comments remain visible to moderators, so moderation does not prevent exposure.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

CVSS Metrics

  • v3.1•CRITICAL•Score: 9.3CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Techniques & Countermeasures

  • CWE-79•Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

    The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

  • CWE-116•Improper Encoding or Escaping of Output

    The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

Affected Systems

  • contao•contao

    ≥ 4.0.0, < 5.3.50 | ≥ 5.4.0-RC1, < 5.7.12

References (4)