CVE-2026-58027 in MediaWiki AbuseFilter
Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation AbuseFilter. This vulnerability is associated with program files includes/Api/QueryAbuseFilters.Php. This issue affects AbuseFilter: from * before 1.46.0, 1.45.4, 1.44.6, 1.43.9.
Quick answer
Wikimedia Foundation MediaWiki AbuseFilter should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- MediaWiki AbuseFilter before 1.46.0, 1.45.4, 1.44.6, and 1.43.9
Fixed versions
- MediaWiki 1.46.0, 1.45.4, 1.44.6, or 1.43.9 or later on the supported branch
How to fix it
CVE-2026-58027 affects MediaWiki AbuseFilter. In simple terms, an attacker may be able to see data they should not see. Check for MediaWiki AbuseFilter before 1.46.0, 1.45.4, 1.44.6, and 1.43.9 and update to MediaWiki 1.46.0, 1.45.4, 1.44.6, or 1.43.9 or later on the supported branch. Limit risky wiki actions and keep public pages monitored until the update is installed.
- Find every MediaWiki AbuseFilter install in production, staging, and test.
- Check whether it matches MediaWiki AbuseFilter before 1.46.0, 1.45.4, 1.44.6, and 1.43.9.
- Update to MediaWiki 1.46.0, 1.45.4, 1.44.6, or 1.43.9 or later on the supported branch.
- Limit risky wiki actions and keep public pages monitored until the update is installed.
- Back up the system before making the change.
- Review logs for strange requests, crashes, file changes, or failed actions.
- Rotate secrets or rebuild the host if you suspect the issue was used.
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Verify the fix
- Confirm the installed version is fixed or the mitigation is active.
- Confirm untrusted users cannot reach the risky feature or service.
- Test the affected feature with a normal user account.
- Review recent logs for signs of abuse.
- Run a fresh Fixnx scan and keep the result with the change record.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-58027?
Wikimedia Foundation MediaWiki AbuseFilter versions listed as affected should be reviewed: MediaWiki AbuseFilter before 1.46.0, 1.45.4, 1.44.6, and 1.43.9.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.