Winter: Stored XSS through Brand Settings custom styles (CVE-2026-32257) | HOL Guard CVE

High · CVSS 8.1CVE-2026-32257GHSA-V7CF-8GH9-GXMJ

Winter: Stored XSS through Brand Settings custom styles

Answer in brief

CVE-2026-32257 records a High severity (CVSS 8.1) vulnerability in Winter: Stored XSS through Brand Settings custom styles. The current sources do not mark it as known exploited. The current feed maps winter/wn-backend-module (composer), wintercms/winter (generic), winter/wn-backend-module (packagist). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 12, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.1
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps winter/wn-backend-module (composer), wintercms/winter (generic), winter/wn-backend-module (packagist). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
winter/wn-backend-modulecomposer	<=1.2.12	1.2.13
wintercms/wintergeneric	< 1.2.13	Not reported
winter/wn-backend-modulepackagist	>=0 <1.2.13	1.2.13

Recommended response

Check inventory. Check lockfiles and deployed manifests for winter/wn-backend-module, wintercms/winter, winter/wn-backend-module.
Review the reported fix. Update winter/wn-backend-module to 1.2.13; winter/wn-backend-module to 1.2.13 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 12, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.