Flow colon-separator and flow-guidedtour-optin-welcome-description messages allow stored XSS

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Affected scope and exposure questions

The current feed maps Wikimedia Foundation/Mediawiki - Flow Extension (generic). Check affected ranges and fixed versions before updating.

Recommended response

1. 1Check inventory. Check lockfiles and deployed manifests for Wikimedia Foundation/Mediawiki - Flow Extension.
2. 2Review the reported fix. Update Wikimedia Foundation/Mediawiki - Flow Extension to 1.46.1, 1.45.5, 1.43.10 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

1. Published upstream

   Sep 29, 2026

   Evidence: source:cvelist:source_dates:source-dates:record

2. Source modified

   Sep 29, 2026

   Evidence: source:cvelist:source_dates:source-dates:record

3. First seen by HOL

   Sep 29, 2026

Sources and claim methodology

• Source referencegerrit.wikimedia.org
• Source referencephabricator.wikimedia.org

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