CVE-2026-34090

Suggested investigations: Handle suppressed usernames

State: Published
Severity: 4.8 Medium
Published: May 11, 2026
Updated: May 11, 2026
Reserved: Mar 25, 2026

Description

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation CheckUser.

This issue affects CheckUser: from 1.45.0 before 1.45.2.

Scores

CVSS	Score	Vector	Source
4.0	4.8 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/R:U	wikimedia-foundation

Weaknesses

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Affected Products

Product	Versions
CheckUserWikimedia Foundation	1.45.0 to before 1.45.2Affected

References

https://phabricator.wikimedia.org/T411366

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