CVE-2026-34090 - Vulnerability Details - OpenCVE

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.

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Wikimedia Foundation

CheckUser

unaffected

Version	Status	Constraints
`1.45.0`	affected	< 1.45.2

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References

Link	Providers
https://phabricator.wikimedia.org/T411366

History

Mon, 11 May 2026 16:15:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Mon, 11 May 2026 15:30:00 +0000

Type	Values Removed	Values Added
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.
Title		Suggested investigations: Handle suppressed usernames
Weaknesses		CWE-200
References		https://phabricator.wikimedia.org/T411366
Metrics		cvssV4_0 `{'score': 4.8, 'vector': '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'}`

Projects

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MITRE

Status: PUBLISHED

Assigner: wikimedia-foundation

Published: 2026-05-11T14:50:50.318Z

Updated: 2026-05-11T15:51:32.487Z

Reserved: 2026-03-25T17:15:46.521Z

Link: CVE-2026-34090

Vulnrichment

Updated: 2026-05-11T15:51:27.108Z

NVD

Status : Received

Published: 2026-05-11T16:17:30.407

Modified: 2026-05-11T16:17:30.407

Link: CVE-2026-34090

Redhat

No data.

OpenCVE Enrichment

No data.

Weaknesses

CWE-200

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