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Fencer Intel
medium 4.5

CVE-2026-125338 json

Winter CMS: Stored XSS through cached Brand Settings and Editor Settings custom styles

published 2mo ago modified yesterday also GHSA-5cwr-5jxg-pcf6 , EUVD-2026-122884

cvss
4.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

Winter CMS is a content management system built on the Laravel PHP framework. Prior to 1.2.14, BrandSetting::renderCss() and EditorSetting::renderCss() store raw LESS compiler output with Cache::forever() but apply strip_tags() only to the value returned on a cache miss. The first render after saving custom CSS appears sanitized while priming an unsafe cache entry, and later cache hits return unsanitized output into the backend style element, allowing a user with backend.manage_branding or backend.manage_editor to cause stored cross-site scripting when another backend page renders the styles. The styles also appear on unauthenticated backend sign-in, password restore, and password reset layouts. This issue is fixed in version 1.2.14.

Patch / fix

  • packagist winter/wn-backend-module 1.2.14

Is CVE-2026-125338 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 4.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:N
GitHub 3.1 4.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
packagist winter/wn-backend-module
<1.2.14
1.2.14

Affected products

  • wintercms winter

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.