CVE-2026-56381: Craft CMS - Stored XSS via User Group Name in User Permissions Page

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-21 · updated 2026-10-25
Weakness: CWE-79

Description

Craft CMS from version 5.0.0-RC1 contains a stored cross-site scripting vulnerability in the User Permissions page where user group names are rendered without proper HTML escaping. Attackers with admin access can inject arbitrary JavaScript via the user group name field that executes when other users view or edit permissions.

Affected products

craftcms cms: from 5.0.0-RC1 before 5.8.22 — fixed in 5.8.22

How to fix

Upgrade to a fixed version: craftcms cms 5.8.22. Check the vendor advisory for mitigations.

References

https://github.com/craftcms/cms/security/advisories/GHSA-g3hp-vvqf-8vw6
https://www.vulncheck.com/advisories/craft-cms-stored-xss-via-user-group-name-in-user-permissions-page
https://github.com/craftcms/cms/security/advisories/GHSA-g3hp-vvqf-8vw6

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