GHSA-m8x6-6r63-qvj2
HIGHCross site scripting via canonical tag in Contao
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.
Blast Radius
contao/core-bundle🐘contao/contaoReal-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
Untrusted users can inject malicious code into the canonical tag, which is then executed on the web page (front end).
Patches
Update to Contao 4.13.3.
Workarounds
Disable canonical tags in the root page settings.
References
https://contao.org/en/security-advisories/cross-site-scripting-via-canonical-url
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 | ≥ 4.13.0&&< 4.13.3 | 4.13.3 |
| 🐘Packagist | contao/contao | ≥ 4.13.0&&< 4.13.3 | 4.13.3 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update contao/core-bundle to 4.13.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m8x6-6r63-qvj2 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 pinpoints whether GHSA-m8x6-6r63-qvj2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-m8x6-6r63-qvj2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-m8x6-6r63-qvj2 in your dependencies?
O3 detects GHSA-m8x6-6r63-qvj2 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.