Cross-site scripting in Craft CMS - #VU134676
Published: June 16, 2026
Vulnerability identifier: #VU134676
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Pixel & Tonic, Inc.
Affected software:
Craft CMS
Craft CMS
Detailed vulnerability description
The vulnerability allows a remote attacker to inject arbitrary JavaScript.
The vulnerability exists due to improper neutralization of input in the /actions/app/resource-js endpoint when handling requests with a poisoned Host or X-Forwarded-Host header. A remote attacker can send a specially crafted request to inject arbitrary JavaScript.
If a caching layer is present, the issue can lead to web cache poisoning and stored cross-site scripting in the control panel. The issue manifests when assetManager.cacheSourcePaths is set to false.
Remediation
Install security update from vendor's website.