CVE-2026-32258: Winter: Stored XSS through Editor Settings custom styles

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-26 · updated 2026-09-09
Weakness: CWE-79

Description

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. From 1.2.10 through 1.2.12, authenticated backend users with the backend.manage_editor permission can store custom Markup Styles that are compiled by the LESS parser and rendered without sanitization on every backend page, allowing stored cross-site scripting. This issue is fixed in version 1.2.13.

Affected products

wintercms winter: from 1.2.10, < 1.2.13

References

https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720
https://github.com/wintercms/winter/security/advisories/GHSA-vgp4-2fc4-qff2

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