XSS in Wintercms Winter

CVE-2026-32257

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.2.13, custom CSS supplied through the Brand Settings Styles field by a backend user with the backend.manage_branding permission is compiled by the LESS parser and rendered without sanitization on every backend page, allowing stored cross-site scripting against backend users. This issue is fixed in version 1.2.13.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (30.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-32257: held from 0.002 to 0.004.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-32257?
CVE-2026-32257 is a high-severity vulnerability in Wintercms Winter, classified under Cross-site Scripting. CVSS score: 8.1/10. Published 2026-08-26.
How severe is CVE-2026-32257?
High severity. CVSS v3 base score is 8.1 out of 10.