Winter CMS has Stored Cross-site Scripting (XSS) in Asset Manager

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

• CVE-2026-22254: 0.29% estimated exploitation activity in the next 30 days; percentile 21.21 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Affected versions of Winter CMS allow users with access to the CMS Asset Manager were able to upload SVGs without automatic sanitization. To actively exploit this security issue, an attacker would need access to the Backend with a user account with the following permission: cms.manageassets The Winter CMS maintainers strongly recommend that the cms.manageassets permission only be reserved to trusted administrators and developers in general. Patches Sanitization of SVG assets is now applied automatically when uploading through the CMS Asset Manager. This security issue has been fixed as of https://github.com/wintercms/winter/commit/8a7f74b004fcd19721764fc63af0cdb339d9fb65. Workarounds If users cannot upgrade, they may apply commit https://github.com/wintercms/winter/commit/8a7f74b004fcd19721764fc63af0cdb339d9fb65 to their Winter CMS installation manually to resolve this issue.

Published by the source

4 Feb 2026, 21:32 UTC

Last modified by the source

6 Feb 2026, 21:42 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m7gw-rffq-rxjm

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# Patch Next advisory brief: CVE-2026-22254

Advisory: Winter CMS has Stored Cross-site Scripting (XSS) in Asset Manager
IDs: CVE-2026-22254, GHSA-m7gw-rffq-rxjm
Record: https://patchnext.com/advisories/cve-2026-22254 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: winter/wn-cms-module 1.2.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist winter/wn-cms-module: affected <= 1.2.9; fixed in 1.2.10

## Suggested inspection (read-only)
- Packagist winter/wn-cms-module: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on winter/wn-cms-module.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m7gw-rffq-rxjm (GitHub-reviewed advisory GHSA-m7gw-rffq-rxjm lists affected ranges: Packagist winter/wn-cms-module >=0 <=1.2.9)

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