# CVE-2026-58031: Wikimedia Foundation MediaWiki XSS in ApiSandboxLayout

Source: https://junglewise.ai/threats/cve-2026-58031-wikimedia-foundation-mediawiki-xss-in-apisandboxlayout  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-01. Updated: 2026-07-01  
License: CC BY 4.0 with a link back

CVE-2026-58031 · Severity: info · CVSS 0 · Published 2026-07-01

MediaWiki, the software powering Wikipedia and many other wikis, contains a security flaw in its API Sandbox tool. This tool is used by developers to test how the website communicates with other applications. An attacker could potentially use this flaw to run unauthorized scripts in a user's browser, though the reported impact is minimal and requires the attacker to have a user account.

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

## Quick answers

**Is CVE-2026-58031 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-58031 being exploited in the wild.

**How severe is CVE-2026-58031?** Informational severity, with a CVSS score of 0, published 1 July 2026.

**Which products and versions are affected?** Wikimedia Foundation MediaWiki 1.46.0-rc.0 to 1.46.0.

**Is there a fix for CVE-2026-58031?** 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-2026-58031 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-58031?** 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 cross-site scripting (XSS) vulnerability exists in MediaWiki's ApiSandboxLayout.js component. The flaw is caused by improper neutralization of input during web page generation within the Special:ApiSandbox interface. An attacker with basic user privileges (PR:L) could potentially inject malicious scripts that execute in the context of another user's session, provided there is user interaction (UI:P). The vulnerability specifically affects versions 1.46.0-rc.0 through 1.46.0. While the CNA has assigned a CVSS score of 0.0, the vulnerability is tracked as CWE-79.

## Affected products

- Wikimedia Foundation MediaWiki 1.46.0-rc.0 to 1.46.0

## Timeline

- 2026-07-01: advisory: NVD publication date

## References

- [https://phabricator.wikimedia.org/T426889](https://phabricator.wikimedia.org/T426889)

## 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)