GHSA-2mvg-c6mg-3q63
MEDIUMGHSA-2mvg-c6mg-3q63 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in concrete5/concrete5. 5 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-2mvg-c6mg-3q63 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Concrete CMS vulnerable to cross-site scripting (XSS)
Blast Radius
concrete5/concrete5Real-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
concrete5 8.1.0 places incorrect trust in the HTTP Host header during caching, if the administrator did not define a "canonical" URL on installation of concrete5 using the "Advanced Options" settings. Remote attackers can make a GET request with any domain name in the Host header. This is stored and allows for arbitrary domains to be set for certain links displayed to subsequent visitors, potentially an XSS vector.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | concrete5/concrete5 | all versions | No fix |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Concrete5 CMS 8.1.0 - 'Host' Header Injection
by hyp3rlinx · Apr 14, 2017
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for concrete5/concrete5. 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.
Remediation status
No patched version of concrete5/concrete5 has shipped for GHSA-2mvg-c6mg-3q63 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2mvg-c6mg-3q63 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-2mvg-c6mg-3q63. 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-2mvg-c6mg-3q63 in your dependencies?
O3 detects GHSA-2mvg-c6mg-3q63 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.