CVE-2026-27591 PUBLISHED

Winter: Privilege escalation by authenticated backend users

Assigner: GitHub_M
Reserved: 20.02.2026 Published: 11.03.2026 Updated: 12.03.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 10

Product Status

Vendor wintercms
Product winter
Versions
  • Version >= 1.2.0, < 1.2.12 is affected
  • Version >= 1.1.0, < 1.1.12 is affected
  • Version < 1.0.477 is affected

References

Problem Types

  • CWE-284: Improper Access Control CWE
  • CWE-639: Authorization Bypass Through User-Controlled Key CWE
  • CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes CWE