Winter: Stored XSS through Backend List widget image columns

Exploitation

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

CVSS

2.0 · CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact Backend\Widgets\Lists::evalImageTypeValue() interpolated the resolved image URL into a single-quoted src attribute without escaping it. Where a list column of type image rendered an attacker-influenced value, that value could break out of the attribute and inject arbitrary attributes — including event handlers — into the backend list, executing in the session of whichever backend user viewed it. Winter core ships no image list column, so a default installation is unaffected. Exploitation requires a plugin that renders attacker-influenced values through one. The supported image sources are plugins, themes, the Media Library, the uploads directory, and Attach\File models; an arbitrary external URL is not among them. ImageResizer::filterGetUrl() returns the value it was given when it cannot resolve an image, however, so an unsupported value reached the attribute verbatim rather than being rejected. As with previous issues of this kind the severity is limited: an attacker must…

Published by the source

20 Aug 2026, 18:44 UTC

Last modified by the source

20 Aug 2026, 19:00 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7mpf-4465-7fc2

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7mpf-4465-7fc2

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# Patch Next advisory brief: GHSA-7mpf-4465-7fc2

Advisory: Winter: Stored XSS through Backend List widget image columns
IDs: GHSA-7mpf-4465-7fc2
Record: https://patchnext.com/advisories/ghsa-7mpf-4465-7fc2 (revision 2, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: winter/wn-backend-module 1.2.14. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist winter/wn-backend-module: affected >= 1.1.0, < 1.2.14; fixed in 1.2.14

## Suggested inspection (read-only)
- Packagist winter/wn-backend-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-backend-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://osv.dev/vulnerability/GHSA-7mpf-4465-7fc2 (OSV record GHSA-7mpf-4465-7fc2 lists affected ranges: Packagist winter/wn-backend-module >=1.1.0 <1.2.14 (fixed))
- Verified: https://github.com/advisories/GHSA-7mpf-4465-7fc2 (GitHub-reviewed advisory GHSA-7mpf-4465-7fc2 lists affected ranges: Packagist winter/wn-backend-module >=1.1.0 <1.2.14)

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