Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-44011: 0.62% estimated exploitation activity in the next 30 days; percentile 49.78 (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.

We identified a vulnerability in the latest version of Craft CMS which contains an input-handling flaw in a Yii object creation path that let any authenticated user inject malicious configuration and execute arbitrary commands on the server. Yii’s dynamic object configuration, as implemented in Craft CMS, is a feature that lets the application build parts of itself from a settings list. This is largely a continuation of https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5, but through a different path that was not mitigated in the original. The request-controlled condition field layouts data is converted into a live FieldLayout object without a Component::cleanseConfig() boundary. Because Craft configures models before parent::construct(), attacker-controlled special config keys can take effect during object creation, and FieldLayout initialization then triggers a same-request event. This appears to be another variant of the recent object-config /…

Published by the source

6 May 2026, 17:54 UTC

Last modified by the source

13 May 2026, 16:29 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qrgm-p9w5-rrfw

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-44011

Advisory: Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior
IDs: CVE-2026-44011, GHSA-qrgm-p9w5-rrfw
Record: https://patchnext.com/advisories/cve-2026-44011 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.9.18, 4.17.12. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 4.0.0, < 4.17.12; >= 5.0.0, < 5.9.18; fixed in 5.9.18, 4.17.12

## 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-qrgm-p9w5-rrfw (GitHub-reviewed advisory GHSA-qrgm-p9w5-rrfw lists affected ranges: Packagist craftcms/cms >=4.0.0 =5.0.0 <5.9.18)

Commands are suggestions: review each one before running it.