# CVE-2026-34091: Wikimedia Foundation MediaWiki sensitive information disclosure

Source: https://junglewise.ai/threats/cve-2026-34091-wikimedia-foundation-mediawiki-sensitive-information-disclosure  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-11. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-34091 · Severity: high · CVSS 7.5 · Published 2026-05-11

A vulnerability in MediaWiki, the software used to power Wikipedia and many other corporate wikis, allows unauthorized individuals to access sensitive information. This could lead to the exposure of internal data or configuration details that should remain private. Organizations using MediaWiki should update to the latest patched versions to protect their data integrity and privacy.

Technologies: [Wikimedia Foundation MediaWiki](https://junglewise.ai/threats/technologies/mediawiki). Vendors: [Wikimedia Foundation](https://junglewise.ai/threats/vendors/wikimedia-foundation).

## Quick answers

**Is CVE-2026-34091 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34091 being exploited in the wild.

**How severe is CVE-2026-34091?** High severity, with a CVSS score of 7.5, published 11 May 2026.

**Which products and versions are affected?** Wikimedia Foundation MediaWiki before 1.43.7, 1.44.4, 1.45.2, Before 1.43.7, 1.44.4, 1.45.2.

**Is there a fix for CVE-2026-34091?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-34091 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-34091?** Check whether you run Wikimedia Foundation MediaWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) vulnerability exists in Wikimedia Foundation MediaWiki. The flaw allows a remote, unauthenticated attacker to access information that is intended to be restricted. The vulnerability is reachable over the network without user interaction. Patches have been released in versions 1.43.7, 1.44.4, and 1.45.2 to address this information disclosure.

## Affected products

- Wikimedia Foundation MediaWiki before 1.43.7, 1.44.4, 1.45.2

## Timeline

- 2026-05-11: advisory: Initial disclosure by Wikimedia Foundation

## References

- [https://phabricator.wikimedia.org/T411305](https://phabricator.wikimedia.org/T411305)

## Related threats

- [Mediawiki Wikibase Extension stored cross-site scripting](https://junglewise.ai/threats/cve-2026-100245-improper-neutralization-of-input-during-web-page-generation-xss)
- [Wikimedia Mediawiki UploadWizard DOM XSS in Flickr titles](https://junglewise.ai/threats/cve-2026-100381-improper-neutralization-of-input-during-web-page-generation-xss)
- [MediaWiki Wikibase reflected XSS in Special:SetLabel](https://junglewise.ai/threats/cve-2026-100380-improper-neutralization-of-input-during-web-page-generation-xss)
- [Wikimedia Foundation MediaWiki XSS in Logging and Special Pages](https://junglewise.ai/threats/cve-2026-58037-wikimedia-foundation-mediawiki-xss-in-logging-and-special-pages)
- [Wikimedia Foundation MediaWiki Information Exposure in User API](https://junglewise.ai/threats/cve-2026-58036-wikimedia-foundation-mediawiki-information-exposure-in-user-api)