# Wikimedia Foundation CheckUser vulnerabilities

Source: https://junglewise.ai/threats/technologies/checkuser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/technologies/checkuser.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 3 vulnerabilities in Wikimedia Foundation CheckUser: 0 in the last 7 days and 1 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2023-37252, was published on 14 September 2026. Nothing in the last four weeks, down from 1 vulnerability in the four before.

## Counts

- Last 7 days: 0
- Last 30 days: 0
- Last 90 days: 1
- All time: 3 (0 critical, 0 exploited in the wild)

## About Wikimedia Foundation CheckUser

CheckUser is a MediaWiki extension that allows administrators to check user information and access patterns on wiki sites.

## Latest Wikimedia Foundation CheckUser vulnerabilities

- [CVE-2023-37252: MediaWiki CheckUser extension information disclosure in log](https://junglewise.ai/threats/cve-2023-37252-mediawiki-checkuser-extension-information-disclosure-in-log) (low, CVSS 3.1, published 14 Sep 2026)
- [CVE-2026-58034: Wikimedia Foundation CheckUser XSS in blockConnectedTempAccountsField](https://junglewise.ai/threats/cve-2026-58034-wikimedia-foundation-checkuser-xss-in) (info, CVSS 0, published 1 Jul 2026)
- [CVE-2026-34090: Wikimedia Foundation CheckUser information exposure in Suggested Investigations](https://junglewise.ai/threats/cve-2026-34090-wikimedia-foundation-checkuser-information-exposure-in-suggested) (high, CVSS 7.5, published 11 May 2026)

## Most severe Wikimedia Foundation CheckUser vulnerabilities

- [CVE-2026-34090: Wikimedia Foundation CheckUser information exposure in Suggested Investigations](https://junglewise.ai/threats/cve-2026-34090-wikimedia-foundation-checkuser-information-exposure-in-suggested) (high, CVSS 7.5, published 11 May 2026)
- [CVE-2023-37252: MediaWiki CheckUser extension information disclosure in log](https://junglewise.ai/threats/cve-2023-37252-mediawiki-checkuser-extension-information-disclosure-in-log) (low, CVSS 3.1, published 14 Sep 2026)
- [CVE-2026-58034: Wikimedia Foundation CheckUser XSS in blockConnectedTempAccountsField](https://junglewise.ai/threats/cve-2026-58034-wikimedia-foundation-checkuser-xss-in) (info, CVSS 0, published 1 Jul 2026)

## Vulnerabilities per week

Nothing in the last four weeks, down from 1 vulnerability in the four before.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 1 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Other Wikimedia Foundation technologies

- [Wikimedia Foundation Mediawiki](https://junglewise.ai/threats/technologies/mediawiki): 21 vulnerabilities
- [Wikimedia Foundation Cargo Extension](https://junglewise.ai/threats/technologies/cargo-extension): 4 vulnerabilities
- [Wikimedia Foundation Mediawiki WikiLambda extension](https://junglewise.ai/threats/technologies/mediawiki-wikilambda-extension): 4 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Wikimedia Foundation CheckUser vulnerabilities", https://junglewise.ai/threats/technologies/checkuser, 9 November 2026.