CVE-2026-27591CWE-284CWE-639CWE-915

Winter: Privilege escalation by authenticated backend users

Critical · published March 11, 2026

CVSS v3.1
10.0
EPSS
1%
Percentile
58.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
10.0 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00860 · 58.1th percentile
Weaknesses
CWE-284 · Improper Access Control; CWE-639 · Authorization Bypass Through User-Controlled Key; CWE-915 · Improperly Controlled Modification of Dynamically-Determined Object Attributes
Published
2026-03-11T21:25Z
EPSS history
Timeline
  • 11 MAR 21:25Z
    Winter: Privilege escalation by authenticated backend users
    cvelistv5