Stored Cross-Site Scripting in Winter CMS Affects Multiple Backend Pages
CVE-2026-32257

8.1HIGH

Key Information:

Vendor

Wintercms

Status
Winter
Vendor
CVE Published:
26 August 2026

What is CVE-2026-32257?

Winter CMS, an open-source content management system built on the Laravel PHP framework, is susceptible to a stored cross-site scripting vulnerability. This issue arises when backend users with the 'backend.manage_branding' permission are allowed to input custom CSS via the Brand Settings Styles field. Prior to version 1.2.13, the LESS parser processes this unverified input, which is then rendered unsanitized across backend pages. This security flaw enables attackers to execute scripts in the context of other backend users, thereby compromising their sessions and sensitive data. The vulnerability has been addressed in the latest update (version 1.2.13), which includes proper sanitization of user inputs.

Affected Version(s)

winter < 1.2.13

References

https://github.com/wintercms/winter/security/advisories/G...
x_refsource_CONFIRM
https://github.com/wintercms/winter/commit/d28f0b9474af79...
x_refsource_MISC

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.