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SVGs uploaded through the CMS AssetManager were not sanitized

Low
LukeTowers published GHSA-m7gw-rffq-rxjm Feb 4, 2026

Package

composer winter/wn-cms-module (Composer)

Affected versions

<=1.2.9

Patched versions

1.2.10

Description

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.

Patches

Sanitization of SVG assets is now applied automatically when uploading through the CMS Asset Manager.

This security issue has been fixed as of 8a7f74b.

Workarounds

If you cannot upgrade, you may apply commit 8a7f74b to your Winter CMS installation manually to resolve this issue.

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:N/A:N

CVE ID

CVE-2026-22254

Weaknesses

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. Learn more on MITRE.

Credits