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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.

PUBLISHED Reserved 2026-02-20 | Published 2026-03-11 | Updated 2026-03-12 | Assigner GitHub_M




CRITICAL: 10.0CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Problem types

CWE-284: Improper Access Control

CWE-639: Authorization Bypass Through User-Controlled Key

CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes

Product status

>= 1.2.0, < 1.2.12
affected

>= 1.1.0, < 1.1.12
affected

< 1.0.477
affected

References

github.com/...winter/security/advisories/GHSA-pgpf-m8m4-6cg6

wintercms.com/releases/v1.0.477

wintercms.com/releases/v1.1.12

wintercms.com/releases/v1.2.12

cve.org (CVE-2026-27591)

nvd.nist.gov (CVE-2026-27591)

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