Craft CMS has a Missing Authorization Check on User Group Removal via save-permissions Action

Exploitation

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

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-41128: 0.25% estimated exploitation activity in the next 30 days; percentile 16.23 (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 The actionSavePermissions() endpoint allows a user with only viewUsers permission to remove arbitrary users from all user groups. While saveUserGroups() enforces per-group authorization for additions, it performs no equivalent authorization check for removals, so submitting an empty groups value removes all existing group memberships. Affected Versions - Craft CMS 5.6.0 through 5.9.14 (latest release at time of report) - Regression introduced in 5.6.0 when the viewUsers permission was added - Prior to 5.6.0, editedUser() required editUsers, which implicitly protected this endpoint - Requires Pro edition or higher (the vulnerable code path is gated by CmsEdition::Pro) Vulnerability Details Root Cause This is a regression introduced in Craft CMS 5.6.0 when the viewUsers permission was added. Before that change, editedUser() required editUsers permission for accessing other users’ data, which implicitly protected actionSavePermissions(). After the change, actionSavePermissions()…

Published by the source

14 Apr 2026, 23:34 UTC

Last modified by the source

24 Apr 2026, 20:42 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jq2f-59pj-p3m3

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# Patch Next advisory brief: CVE-2026-41128

Advisory: Craft CMS has a Missing Authorization Check on User Group Removal via save-permissions Action
IDs: CVE-2026-41128, GHSA-jq2f-59pj-p3m3
Record: https://patchnext.com/advisories/cve-2026-41128 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.9.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 5.6.0, < 5.9.15; fixed in 5.9.15

## 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-jq2f-59pj-p3m3 (GitHub-reviewed advisory GHSA-jq2f-59pj-p3m3 lists affected ranges: Packagist craftcms/cms >=5.6.0 <5.9.15)

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