Cross-site scripting in Grav CMS - CVE-2026-42841
Published: May 5, 2026
Vulnerability identifier: #VU130074
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-42841
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Grav CMS
Affected software:
Grav CMS
Grav CMS
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary JavaScript in a victim's browser.
The vulnerability exists due to cross-site scripting in the Markdown media action handling for rendered image HTML when processing crafted Markdown image references with media action query parameters. A remote privileged user can store a crafted Markdown image reference that injects an executable event-handler attribute to execute arbitrary JavaScript in a victim's browser.
User interaction is required when another user views the affected page.
How to mitigate CVE-2026-42841
Install security update from vendor's website.