BaseFortify

Publication date: 2025-11-25

Last updated on: 2025-12-03

Assigner: GitHub, Inc.

Description

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2025-11-25

Last Modified

2025-12-03

Generated

2026-07-07

AI Q&A

2025-11-25

EPSS Evaluated

2026-07-05

NVD

CVE-2025-65961

Affected Vendors & Products

Vendor	Product	Version / Range
contao	contao	From 4.0.0 (inc) to 4.13.57 (exc)
contao	contao	From 5.0.0 (inc) to 5.3.42 (exc)
contao	contao	From 5.4.0 (inc) to 5.6.5 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-87	The product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.
CWE-79	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.

Attack-Flow Graph

Executive Summary

This vulnerability in Contao CMS allows an attacker to inject code into the template output, which will then be executed in the browser on both the front end and back end. This means malicious code can run within the context of the website, potentially leading to unauthorized actions or data exposure. The issue affects versions from 4.0.0 up to but not including 4.13.57, 5.3.42, and 5.6.5, where it has been patched.

Impact Analysis

The vulnerability can lead to the execution of injected code in users' browsers, which may result in unauthorized access, data leakage, or manipulation of website content. Since the code runs in the context of the website, it could compromise both front end and back end operations, potentially affecting the integrity and confidentiality of the system.

Mitigation Strategies

To mitigate this vulnerability, immediately update Contao to version 4.13.57, 5.3.42, or 5.6.5 or later where the issue is patched. As a workaround, avoid using the affected templates or patch them manually to prevent code injection in the template output.

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