Craft CMS Vulnerable to Stored XSS via User Group Name in User Permissions Page

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

1.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2026-56381: 0.18% estimated exploitation activity in the next 30 days; percentile 7.71 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A stored XSS vulnerability exists in the User Permissions page. The User Group name is rendered without proper HTML escaping in the permissions section, allowing an attacker to execute arbitrary JavaScript when another user views or edits a user's permissions. [!NOTE] This is a separate vulnerability from the previously reported "Stored XSS via User Group Name in User Settings Page" and "Multiple Stored XSS in User Group Edit Page". This affects a different sink: the individual user's permissions page. Proof of Concept Required Permissions - Admin access - allowAdminChanges is enabled in production, which is against our security recommendations. Steps to Reproduce 1. Log in to the control panel as an admin 2. Navigate to Settings → Users → User Groups 3. Create or edit a user group and set the Name field to: 4. Save the user group 5. Navigate to Users and edit any user (/admin/users/{id}) 6. Click on the Permissions tab 7. XSS executes Mitigation Sanitize user group names…

Published by the source

11 Mar 2026, 14:56 UTC

Last modified by the source

6 Aug 2026, 21:37 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g3hp-vvqf-8vw6

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# Patch Next advisory brief: CVE-2026-56381

Advisory: Craft CMS Vulnerable to Stored XSS via User Group Name in User Permissions Page
IDs: CVE-2026-56381, GHSA-g3hp-vvqf-8vw6
Record: https://patchnext.com/advisories/cve-2026-56381 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 1.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.8.22. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 5.0.0-RC1, <= 5.8.21; fixed in 5.8.22

## Suggested inspection (read-only)
- Packagist craftcms/cms: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on craftcms/cms.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-g3hp-vvqf-8vw6 (GitHub-reviewed advisory GHSA-g3hp-vvqf-8vw6 lists affected ranges: Packagist craftcms/cms >=5.0.0-RC1 <=5.8.21)

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