Summary
Winter CMS has Stored Cross-site Scripting (XSS) in Asset Manager
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.
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.manage_assets
The Winter CMS maintainers strongly recommend that the cms.manage_assets permission only be reserved to trusted administrators and developers in general.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is CVE-2026-22254? CVE-2026-22254 is a low-severity cross-site scripting (XSS) vulnerability in winter/wn-cms-module (composer), affecting versions <= 1.2.9. It is fixed in 1.2.10. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which versions of winter/wn-cms-module are affected by CVE-2026-22254? winter/wn-cms-module (composer) versions <= 1.2.9 is affected.
- Is there a fix for CVE-2026-22254? Yes. CVE-2026-22254 is fixed in 1.2.10. Upgrade to this version or later.
- Is CVE-2026-22254 exploitable, and should I be worried? Whether CVE-2026-22254 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-22254 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-22254? Upgrade
winter/wn-cms-moduleto 1.2.10 or later.