Wikimedia CheckUser 1.45.0/1.45.1 information disclosure

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.9$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Wikimedia CheckUser 1.45.0/1.45.1. The affected element is an unknown function. Such manipulation leads to information disclosure. This vulnerability is traded as CVE-2026-34090. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Wikimedia CheckUser 1.45.0/1.45.1. It has been rated as problematic. Affected by this issue is an unknown code block. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. CVE summarizes:

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.

The advisory is available at phabricator.wikimedia.org. This vulnerability is handled as CVE-2026-34090 since 03/25/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are needed for exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

Upgrading to version 1.45.2 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.9

VulDB Base Score: 2.4
VulDB Temp Score: 2.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: CheckUser 1.45.2

Timelineinfo

03/25/2026 CVE reserved
05/11/2026 +46 days Advisory disclosed
05/11/2026 +0 days VulDB entry created
05/18/2026 +7 days VulDB entry last update

Sourcesinfo

Advisory: phabricator.wikimedia.org
Status: Confirmed

CVE: CVE-2026-34090 (🔒)
GCVE (CVE): GCVE-0-2026-34090
GCVE (VulDB): GCVE-100-362654

Entryinfo

Created: 05/11/2026 18:21
Updated: 05/18/2026 11:49
Changes: 05/11/2026 18:21 (68), 05/18/2026 11:49 (11)
Complete: 🔍
Cache ID: 216::103

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Discussion

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