Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation CheckUser. This vulnerability is associated with program files modules/ext.CheckUser/checkuser/checkUserHelper/buildUserElement.Js.

This issue affects CheckUser: from * before 1.44.1.

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

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

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.0002.

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
* affected < 1.44.1

Configuration 1 [-]

cpe:2.3:a:mediawiki:checkuser:*:*:*:*:*:mediawiki:*:*

No data.

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Vendors Products
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Project Subscriptions

Vendors Products
Mediawiki Subscribe
Checkuser Subscribe
Wikimedia Subscribe
Checkuser Subscribe
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/T403408 cve-icon cve-icon
History

Thu, 09 Apr 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Mediawiki
Mediawiki checkuser
CPEs cpe:2.3:a:mediawiki:checkuser:*:*:*:*:*:mediawiki:*:*
Vendors & Products Mediawiki
Mediawiki checkuser
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Wed, 04 Feb 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Wikimedia
Wikimedia checkuser
Vendors & Products Wikimedia
Wikimedia checkuser

Tue, 03 Feb 2026 22:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 03 Feb 2026 13:15:00 +0000

Type Values Removed Values Added
Description Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation CheckUser. This vulnerability is associated with program files modules/ext.CheckUser/checkuser/checkUserHelper/buildUserElement.Js. This issue affects CheckUser: from * before 1.44.1.
Title i18n XSS through Special:CheckUser CheckUser helper
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 0, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N/E:U'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: wikimedia-foundation

Published:

Updated: 2026-02-03T21:08:33.097Z

Reserved: 2025-09-29T13:18:40.094Z

Link: CVE-2025-61651

cve-icon Vulnrichment

Updated: 2026-02-03T21:08:25.420Z

cve-icon NVD

Status : Analyzed

Published: 2026-02-03T02:16:07.407

Modified: 2026-04-09T20:33:09.617

Link: CVE-2025-61651

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-02-04T12:14:21Z

Weaknesses