CVE-2026-100380: Reflected XSS in Wikibase Special:SetLabel language validation

Severity: medium (CVSS 5.3 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-25 · updated 2026-09-28
Weakness: CWE-79

Description

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - Wikibase Extension allows Cross-Site Scripting (XSS). This issue affects Mediawiki - Wikibase Extension: from * before 1.46.1, 1.45.5, 1.43.10.

Affected products

Wikimedia Foundation Mediawiki - Wikibase Extension: before 1.46.1, 1.45.5, 1.43.10 — fixed in 1.43.10, 1.45.5, 1.46.1

How to fix

Upgrade to a fixed version: Wikimedia Foundation Mediawiki - Wikibase Extension 1.43.10, 1.45.5, 1.46.1. Check the vendor advisory for mitigations.

References

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