CVE-2025-61651

i18n XSS through Special:CheckUser CheckUser helper

MEDIUM
6.1
CVSS Score
Published: February 3, 2026 at 12:53 AM UTC
Updated: June 17, 2026 at 09:50 AM UTC
2 products affected across 2 vendorsCheckUserCheckUser

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.44.1
v < 1.44.1
Affected range stops below 1.44.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

Permissions Required
Source: cverecord
https://phabricator.wikimedia.org/T403408

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-79

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