CVE-2026-58027: QueryAbuseFilter API can be used to see the hit count of private filters, which is hidden in the UI

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-01 · updated 2026-10-25
Weakness: CWE-200

Description

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.

Affected products

Wikimedia Foundation MediaWiki: from 1.43.0 before 1.43.9; from 1.44.0 before 1.44.6; from 1.45.0 before 1.45.4; 1.46.0-rc0 — fixed in 1.43.9, 1.44.6, 1.45.4

How to fix

Upgrade to a fixed version: Wikimedia Foundation MediaWiki 1.43.9, 1.44.6, 1.45.4. Check the vendor advisory for mitigations.

References

https://phabricator.wikimedia.org/T406954

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