Craft CMS 4.8.0 through 4.18.5 and 5.0.0 through 5.10.12 sign an authenticated user's attacker-controlled license-shun cookie with the same key and format used to validate signed redirect parameters, because the HMAC signature is not bound to its purpose (Yii's cookieValidationKey is derived from the same Craft securityKey used for signed request parameters). An authenticated, non-administrator user (Control Panel access is not required) can set the cookie via the license-shun endpoint and transplant the signed envelope into the redirect parameter; on a successful login, Craft validates the signature and renders the authenticated bytes as an unsandboxed Twig template, where Twig's map filter accepts a string callback and allows PHP system() to execute arbitrary operating-system commands as the web-server user. Exploitation requires an account using password authentication without active 2FA, the default request configuration, and availability of PHP system(). The issue is fixed in 4.18.6 and 5.10.13.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 16 Sep 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Craft CMS 4.8.0 through 4.18.5 and 5.0.0 through 5.10.12 sign an authenticated user's attacker-controlled license-shun cookie with the same key and format used to validate signed redirect parameters, because the HMAC signature is not bound to its purpose (Yii's cookieValidationKey is derived from the same Craft securityKey used for signed request parameters). An authenticated, non-administrator user (Control Panel access is not required) can set the cookie via the license-shun endpoint and transplant the signed envelope into the redirect parameter; on a successful login, Craft validates the signature and renders the authenticated bytes as an unsandboxed Twig template, where Twig's map filter accepts a string callback and allows PHP system() to execute arbitrary operating-system commands as the web-server user. Exploitation requires an account using password authentication without active 2FA, the default request configuration, and availability of PHP system(). The issue is fixed in 4.18.6 and 5.10.13. | |
| Title | Craft CMS before 4.18.6 Remote Code Execution via signed cookie | |
| First Time appeared |
Craftcms
Craftcms craft Cms |
|
| Weaknesses | CWE-1336 | |
| CPEs | cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Craftcms
Craftcms craft Cms |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-09-16T21:46:57.949Z
Reserved: 2026-09-16T13:47:49.170Z
Link: CVE-2026-92592
No data.
Status : Received
Published: 2026-09-16T22:18:30.013
Modified: 2026-09-16T22:18:30.013
Link: CVE-2026-92592
No data.
OpenCVE Enrichment
No data.
Weaknesses