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Low

Contao: Cross-site request forgery in custom backend actions

  • Disclosed: 09.10.2026
  • Updated: 11.10.2026 10:31

RequestTokenListener is the only generic REQUEST_TOKEN validator in Contao, and it executes exclusively on POST requests. For GET requests, the protection is local and declarative, triggering only when an act parameter is present. Any backend action dispatched through a different parameter therefore lacks CSRF protection entirely. This represents a systemic family of issues rather than an isolated bug.

Impact

An attacker who convinces an authenticated backend user to load a crafted URL can trigger backend actions on behalf of that user without requiring a token or confirmation. Because the exposure stems from the dispatch mechanism rather than a single callback, all present and future key= actions inherit this vulnerability.

Scope and Constraints: The victim must be authenticated in the backend and must load the URL. Furthermore, reachable actions are limited to the modules the user is authorized to access. No key= action was found that grants privileges; verified actions were destructive or state-changing rather than privilege-escalating.

What to do

Update contao/core-bundle to version 5.3.50, 5.7.12, or later.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package contao/core-bundle >= 4.0.0, < 5.3.50, >= 5.4.0-RC1, < 5.7.12 5.3.50, 5.7.12

References

CVSS score 3.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-352
Platform
Composer
Package
contao/core-bundle
Disclosed
09.10.2026
Updated
11.10.2026 10:31

Sources and licenses · Edited or translated by DockRay; source rights and applicable licenses are retained.

OSV / GitHub Advisory Database - GHSA-9ff2-p842-45wq - CC BY 4.0

Vulnerability history: contao/core-bundle

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (40) in the archive
Total entries
40
First → latest
12.2019 10.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 4
  • High 7
  • Medium 23
  • Low 6

Disclosures per year

Severity:
  1. Contao: Cross-site request forgery in custom backend actions this entry
    Low · 3.5 CVE-2026-107848 >= 4.0.0, < 5.3.50, >= 5.4.0-RC1, < 5.7.12 5.3.50, 5.7.12
  2. Contao affected by remote command execution through file upload
    High · 8.3 CVE-2024-45398 >= 4.0.0, < 4.13.49, >= 5.0.0, < 5.3.15, >= 5.4.0, < 5.4.3 4.13.49, 5.3.15, 5.4.3
  3. Contao: Possible cookie sharing with external domains while checking protected pages for broken links
    High · 8.3 CVE-2024-28235 >= 4.9.0, < 4.13.40, >= 5.0.0-RC1, < 5.3.4 4.13.40, 5.3.4
  4. Contao SQL injection in the file manager
    Critical · 9.8 CVE-2019-11512 >= 4.1.0, < 4.4.39, >= 4.5.0, < 4.7.5 4.4.39, 4.7.5
  5. Contao SQL injection in the backend and listing module
    Critical · 9.8 CVE-2017-16558 >= 4.0.0, < 4.4.8, >= 3.0.0, <= 3.5.30 4.4.8
  6. Cross site scripting via canonical tag in Contao
    High · 7.2 CVE-2022-24899 >= 4.13.0, < 4.13.3 4.13.3
  7. Contao CSRF Token Bypass
    High · 8.8 CVE-2019-10642 >= 4.7.0, < 4.7.3 4.7.3
  8. Contao Does Not Invalidate Existing Sessions When Password Changes
    Critical · 9.8 CVE-2019-10641 >= 4.0.0, < 4.4.37, >= 4.5.0, < 4.7.3 4.4.37, 4.7.3
  9. Contao Core directory traversal vulnerability
    High · 8.8 CVE-2017-10993 >= 4.0.0, < 4.4.1 4.4.1
  10. Contao Does Not Expire Tokens Correctly
    Critical · 9.8 CVE-2019-10643 >= 4.7.0, < 4.7.3 4.7.3
  11. Privilege escalation via form generator
    High · 8.0 CVE-2021-37627 >= 4.0.0, < 4.4.56, >= 4.5.0, < 4.9.18, >= 4.10.0, < 4.11.7 4.4.56, 4.9.18, 4.11.7
  12. Unrestricted file uploads in Contao
    High · 8.8 CVE-2019-19745 >= 4.0.0, < 4.4.46, >= 4.5.0, < 4.8.6 4.4.46, 4.8.6

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