CVE-2025-29790 — contao/core-bundle
CVE-2025-29790 is a Cross-site Scripting (XSS) vulnerability in contao/core-bundle. A fix is available for contao/core-bundle — see the affected versions and patch details below.
Contao allows cross-site scripting through SVG uploads
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-29790.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
contao/core-bundle🐘contao/core-bundle🐘contao/core-bundleReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Users can upload SVG files with malicious code, which is then executed in the back end and/or front end.
Patches
Update to Contao 4.13.54, 5.3.30 or 5.5.6.
Workarounds
Remove svg,svgz from the allowed upload file types in the system settings and from contao.editable_files in the config.yaml.
References
https://contao.org/en/security-advisories/cross-site-scripting-through-svg-uploads
For more information
If you have any questions or comments about this advisory, open an issue in contao/contao.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | contao/core-bundle | ≥ 4.0.0&&< 4.13.54 | 4.13.54composer require contao/core-bundle:^4.13.54 |
| 🐘Packagist | contao/core-bundle | ≥ 5.3.0&&< 5.3.30 | 5.3.30composer require contao/core-bundle:^5.3.30 |
| 🐘Packagist | contao/core-bundle | ≥ 5.4.0&&< 5.5.6 | 5.5.6composer require contao/core-bundle:^5.5.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for contao/core-bundle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update contao/core-bundle to 4.13.54 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-29790 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-29790 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-29790. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-29790 in your dependencies?
O3 Security finds CVE-2025-29790 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.