Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team thanks Alfin Joseph for reporting this issue.
Update concrete5/concrete5 to 9.5.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanConcrete CMS has Stored XSS through its height parameter affects concrete5/concrete5 (composer). Severity is high. Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team thanks Alfin Joseph for reporting this issue.
AI coding agents often install or upgrade packages automatically in composer. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| concrete5/concrete5composer | <9.5.1 | 9.5.1 |
Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team thanks Alfin Joseph for reporting this issue.
Update concrete5/concrete5 to 9.5.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanConcrete CMS has Stored XSS through its height parameter affects concrete5/concrete5 (composer). Severity is high. Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team thanks Alfin Joseph for reporting this issue.
AI coding agents often install or upgrade packages automatically in composer. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| concrete5/concrete5composer | <9.5.1 | 9.5.1 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardFixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard