Which versions of Contao are affected by CVE-2025-29790?

Organizations using Contao should be aware of moderate risk from CVE-2025-29790, a cross-site scripting vulnerability rated CVSS 4.8.. A patch is available.

How to fix or mitigate CVE-2025-29790?

During next maintenance window: Identify affected systems and apply vendor patches when convenient. Verify Content-Security-Policy and output encoding.

Contao CVE-2025-29790

Q: What is the CVSS score of CVE-2025-29790?

CVE-2025-29790 has a CVSS 4.0 base score of 4.8 (Medium). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2025-03-18 security-advisories@github.com

XSS Contao

4.8

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

4.8 MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 18:32 vuln.today

Patch released

Mar 28, 2026 - 18:32 nvd

Patch available

CVE Published

Mar 18, 2025 - 19:15 nvd

MEDIUM 4.8

DescriptionGitHub Advisory

Contao is an Open Source CMS. Users can upload SVG files with malicious code, which is then executed in the back end and/or front end. This vulnerability is fixed in Contao 4.13.54, 5.3.30, or 5.5.6.

AnalysisAI

Contao is an Open Source CMS. Rated medium severity (CVSS 4.8), this vulnerability is remotely exploitable, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.

Technical ContextAI

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. Contao is an Open Source CMS. Users can upload SVG files with malicious code, which is then executed in the back end and/or front end. This vulnerability is fixed in Contao 4.13.54, 5.3.30, or 5.5.6. Affected products include: Contao.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.