Contao: Cross-site request forgery in custom backend actions — GHSA-9FF2-P842-45WQ

Summary

`RequestTokenListener` is the only generic `REQUEST_TOKEN` validator in Contao and it only runs on POST. On the GET side the guard is local and declarative, and it only fires when an `act` parameter is present. Every back end action dispatched through a different parameter therefore has no CSRF protection at all. This is a family rather than a single bug. ### Impact An attacker who gets a logged in back end user to…

Timeline

Published by source

2026-10-09

Risk context

• Reported severity or threat level: low.
• Reported CVSS score: 3.5 out of 10.
• Review exposure for the affected product or family: composer: contao/core-bundle.

Product

composer: contao/core-bundle

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

Evidence and provenance

Canonical advisory ID

GHSA-9FF2-P842-45WQ

Source

GitHub

Vendor

GitHub

Published by source

2026-10-09

Last source activity

2026-10-09

Additional identifiers

CVE-2026-107848

Curated by

hlukh.ch

Related advisories and connections

These advisories are connected by shared CVE, product, vendor, source, or time signals.