# CVE-2026-34095: Wikimedia Foundation MediaWiki incorrect Content-Type in ActionEntryPoint

Source: https://junglewise.ai/threats/cve-2026-34095-wikimedia-foundation-mediawiki-incorrect-content-type-in  
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-2026-34095 · Severity: medium · CVSS 6.1 · Published 2026-05-11

A vulnerability in MediaWiki, the software powering Wikipedia and other wikis, could allow attackers to bypass security protections that prevent malicious code from running in a user's browser. By tricking a user into clicking a specially crafted link to their own user page, an attacker could potentially execute unauthorized scripts within the context of that user's session. This could lead to unauthorized actions being performed on behalf of the user or the theft of sensitive session information.

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

## Quick answers

**Is CVE-2026-34095 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34095 being exploited in the wild.

**How severe is CVE-2026-34095?** Medium severity, with a CVSS score of 6.1, published 11 May 2026.

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

**Is there a fix for CVE-2026-34095?** 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-2026-34095 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-34095?** 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 vulnerability exists in MediaWiki's ActionEntryPoint and FauxResponse components where the 'action=raw' parameter, when used with 'Special:Mypage' subpage titles, fails to correctly apply the requested Content-Type header (e.g., text/javascript). Instead, the application responds with 'text/html'. This occurs because ActionEntryPoint resolves special page redirects using a DerivativeRequest that does not properly propagate headers set by RawAction. An attacker can exploit this by placing malicious content on a victim's user subpage (which may be editable by others depending on wiki configuration) and social engineering the victim into visiting a crafted URL. This results in the browser rendering the page content as arbitrary HTML/JavaScript in the victim's session. The issue is fixed in versions 1.43.7, 1.44.4, and 1.45.2.

## Affected products

- Wikimedia Foundation MediaWiki before 1.43.7, 1.44.4, 1.45.2

## Timeline

- 2026-03-06: disclosed: Issue reported internally via Phabricator.
- 2026-05-11: advisory: CVE-2026-34095 published.

## References

- [https://phabricator.wikimedia.org/T419192](https://phabricator.wikimedia.org/T419192)

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- [Wikimedia Foundation MediaWiki Information Exposure in User API](https://junglewise.ai/threats/cve-2026-58036-wikimedia-foundation-mediawiki-information-exposure-in-user-api)