CVE-2026-34090
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Mediawiki Checkuser
PublishedMay 11, 2026
First seenMay 11, 2026
Weakness typeCWE-200Sensitive information exposure
How to fix
Update
- mediawiki checkuser1.45.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mediawiki checkuser | 1.45.0 ≤ v < 1.45.2 | 1.45.2 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.