CVE-2026-34090 Details
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.
A vulnerability in the CheckUser extension of Wikimedia Foundation allows for the exposure of suppressed usernames to unauthorized users. This issue affects CheckUser versions 1.45.0 prior to 1.45.2. The vulnerability arises because the Special:SuggestedInvestigations page does not properly hide suppressed usernames from users without the right to view them.
The vulnerability has been patched in version 1.45.2. Users should update to this version to address the issue.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 11, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://phabricator.wikimedia.org/T411366 | wikimedia-foundation | Issue TrackingPatch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-200 | Exposure of Sensitive Information to an Unauthorized Actor | wikimedia-foundation |
Affected Products
| Product | Versions |
|---|---|
| mediawiki checkuser | >= 1.45.0, < 1.45.2 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | wikimedia-foundation |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 14, 2026 | Initial Analysis | [email protected] |
| May 11, 2026 | New CVE Received | wikimedia-foundation |