CVE intelligence and bounded remediation

CVE-2025-65961 — Contao is an Open Source CMS

Medium CVSS 4.8

Contao is an Open Source CMS. From version 4.0.0 to before 4.13.57, before 5.3.42, and before 5.6.5, it is possible to inject code into the template output that will be executed in the browser in the front end and back end. This issue has been patched in versions 4.13.57, 5.3.42, and 5.6.5. A workaround for this issue involves not using the affected templates or patch them manually.

Severity
Medium
CVSS
4.8 (3.1)
Published
2025-11-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-87, CWE-79

Affected products

  • contao / contao

Showing 1 representative product identities from 3 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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