# CVE-2026-27591

## Summary

- **CVE ID:** CVE-2026-27591
- **Severity:** CRITICAL
- **CVSS Score:** 10 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** CWE-284, CWE-639, CWE-915
- **Published:** Mar 11, 2026
- **Last Modified:** Mar 12, 2026

## Description

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.

## Affected Products

- wintercms — winter (>= 1.2.0, < 1.2.12)
- wintercms — winter (>= 1.1.0, < 1.1.12)
- wintercms — winter (< 1.0.477)

## References

- [CNA](https://github.com/wintercms/winter/security/advisories/GHSA-pgpf-m8m4-6cg6)
- [CNA](https://wintercms.com/releases/v1.0.477)
- [CNA](https://wintercms.com/releases/v1.1.12)
- [CNA](https://wintercms.com/releases/v1.2.12)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.49%
- **EPSS Percentile:** 40.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._