Craft CMS before 4.18.6 Remote Code Execution via signed cookie

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.

Scores

EPSS (exploitation in 30 days)

0.65% · top 49% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.

Weakness

• CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine (opens in a new tab)All about CWE-1336 and its CVEs

Affected products

• craftcms · cms

  • affected 4.8.0 – < 4.18.6
  • unaffected 4.18.6

• craftcms · cms

  • affected 5.0.0 – < 5.10.13
  • unaffected 5.10.13

References (2)

• GitHub Security Advisory (GHSA-5r92-75j8-c534) (opens in a new tab)vendor-advisory
• VulnCheck Advisory: Craft CMS before 4.18.6 Remote Code Execution via signed cookie (opens in a new tab)third-party-advisory

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-92592](https://trackcve.app/badge/CVE-2026-92592.svg)](https://trackcve.app/cve/CVE-2026-92592)

Record last updated 17 Sept 2026, 19:23 UTC.