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Vulnerabilities

Vulnerability · CVE-2026-107845

Contao: Cross-site scripting in the comments bundle

Published Oct 9, 2026 · catalog updated Oct 9, 2026 · Contao: Cross-site scripting in

Check if you run it

No confirmed exploitation is on record for CVE-2026-107845. EPSS is 0.27%. Act only if a listed version of Contao: Cross-site scripting in is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Contao: Cross-site scripting in).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.27%
Remediation
Advisory link
Affected products
Packagist contao/comments-bundle

An unauthenticated front end visitor can post a comment containing a XSS injection. The victim is any back end user who opens the Comments module, and moderation makes exposure certain rather than preventing it. No header is sent on the Contao back end, so nothing mitigates the inline handler. ### Impact Anyone on the internet can inject script that executes in the Contao back end origin, under the session of whichever user opens the Comments module, with no click and no hover. From there the payload acts as that user through the back end: reading any module they can reach, creating a new administrator, or editing a template, which on Contao is a documented path from back end write access to code execution. Moderation does not help and in fact guarantees exposure, since unpublished comments are still inserted and a moderator has to open the list to act on them.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Packagist contao/comments-bundle4.0.0 → 5.3.50
  • Packagist contao/comments-bundle5.4.0-RC1 → 5.7.12

How to fix CVE-2026-107845

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-107845. EPSS is 0.27%. Act only if a listed version of Contao: Cross-site scripting in is installed.

Which versions are affected?

Compare what you have installed with 4.0.0 → 5.3.50, 5.4.0-RC1 → 5.7.12. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-116; CWE-79: Cross-site Scripting (XSS). EPSS 0.27%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 9, 2026 · Catalog

    Detected

    An unauthenticated front end visitor can post a comment containing a XSS injection. The victim is any back end user who opens the Comments module, and moderation makes exposure certain rather than preventing it. No header is sent on the Contao back end, so nothing mitigates the inline handler. ### Impact Anyone on the internet can inject script that executes in the Contao back end origin, under th

  2. Oct 9, 2026 · Catalog

    Fix available

    Packagist contao/comments-bundle 4.0.0 → 5.3.50

  3. Oct 9, 2026 · Catalog

    Fix available

    Packagist contao/comments-bundle 5.4.0-RC1 → 5.7.12

  4. Oct 9, 2026 · GitHub Advisory Database

    Fix available

    contao/comments-bundle fixed in 5.3.50; contao/comments-bundle fixed in 5.7.12

  5. Oct 9, 2026 · GitHub Advisory Database

    Fix available

    contao/comments-bundle fixed in 5.3.50

  6. Oct 9, 2026 · GitHub Advisory Database

    Fix available

    contao/comments-bundle fixed in 5.7.12

  7. Oct 9, 2026 · Catalog

    Updated

    An unauthenticated front end visitor can post a comment containing a XSS injection. The victim is any back end user who opens the Comments module, and moderation makes exposure certain rather than preventing it. No header is sent on the Contao back end, so nothing mitigates the inline handler. ### Impact Anyone on the internet can inject script that executes in the Contao back end origin, under th

Sources

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.