Is CVE-2026-100381 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100381 being exploited in the wild.

How severe is CVE-2026-100381?

Informational severity, published 25 September 2026.

Which products and versions are affected?

Wikimedia Foundation MediaWiki before 1.46.1, 1.45.5, 1.43.10.

Is there a fix for CVE-2026-100381?

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-2026-100381 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-100381?

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.

CVE-2026-100381: Wikimedia Mediawiki UploadWizard DOM XSS in Flickr titles

CVE-2026-100381 · Severity: info · Published 2026-09-25

MediaWiki's UploadWizard extension, which allows users to upload media files to wikis, contains a cross-site scripting vulnerability in its Flickr integration. An attacker who controls a Flickr collection or set can inject malicious HTML into the collection title, causing arbitrary JavaScript to execute in the browser of any wiki user who attempts to import from that collection. This allows the attacker to perform actions as the victim user, including authenticated API requests, without requiring any special wiki permissions.

Technologies: Wikimedia Foundation MediaWiki. Vendors: Wikimedia Foundation.

Quick answers

Is CVE-2026-100381 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100381 being exploited in the wild.
How severe is CVE-2026-100381?: Informational severity, published 25 September 2026.
Which products and versions are affected?: Wikimedia Foundation MediaWiki before 1.46.1, 1.45.5, 1.43.10.
Is there a fix for CVE-2026-100381?: 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-2026-100381 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-100381?: 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

The vulnerability is a DOM-based XSS (CWE-79) in the Flickr collection/set title processing logic within mw.FlickrChecker.js. The code uses jQuery's .append() method to insert Flickr-supplied collection and set titles directly as HTML strings rather than text nodes, allowing an attacker-controlled Flickr title containing markup like <img src=x onerror=alert()> to execute JavaScript in the wiki origin. The attack requires the victim to have upload-from-URL permissions and Flickr integration enabled, but no wiki edit permissions or administrative actions from the attacker are needed.

Affected products

Wikimedia Foundation Mediawiki before 1.46.1, 1.45.5, 1.43.10

Timeline

2026-09-25: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.