What’s Vulnerable › Vulnerabilities

CVE-2026-42841: Grav: Stored XSS via Markdown media attribute() action in Grav CMS

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-11 · updated 2026-10-26
• Weakness: CWE-79

Description

Grav is a file-based Web platform. Prior to 2.0.0-beta.2, an authenticated user with page editing permissions can inject an executable JavaScript event-handler attribute into rendered image HTML through Grav's Markdown media action syntax. The issue is caused by Markdown image query parameters being converted into callable media actions. The public attribute() media method can be reached this way, allowing an editor to set an arbitrary HTML attribute name and value on the generated image element. This vulnerability is fixed in 2.0.0-beta.2.

Affected products

• getgrav grav: through 1.8.0; 2.0.0-beta1

References

• https://github.com/getgrav/grav/commit/5a12f9be8314682c8713e569e330f11805d0a663
• https://github.com/getgrav/grav/security/advisories/GHSA-r7fx-8g49-7hhr
• https://github.com/getgrav/grav/security/advisories/GHSA-r7fx-8g49-7hhr

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