Critical severity · published Mar 11, 2026
CVE-2026-27591
Winter: Privilege escalation by authenticated backend users
9.9
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WI
winter · wintercms
>= 1.2.0, < 1.2.12; >= 1.1.0, < 1.1.12; < 1.0.477 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27591
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27591
Patch
https://github.com/wintercms/winter/security/advisories/GHSA-pgpf-m8m4-6cg6
Release Notes
https://wintercms.com/releases/v1.0.477
Release Notes
https://wintercms.com/releases/v1.1.12
Release Notes
https://wintercms.com/releases/v1.2.12
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