Is CVE-2026-100238 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100238 being exploited in the wild.

How severe is CVE-2026-100238?

Informational severity, published 29 September 2026.

Which products and versions are affected?

Wikimedia Foundation Mediawiki Flow Extension before 1.46.1, 1.45.5, 1.43.10.

Is there a fix for CVE-2026-100238?

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-2026-100238 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-100238?

Check whether you run Wikimedia Foundation Mediawiki Flow Extension 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-2026-100238: Wikimedia Mediawiki Flow Extension stored XSS

CVE-2026-100238 · Severity: info · Published 2026-09-29

Mediawiki's Flow discussion extension contains a stored cross-site scripting (XSS) vulnerability that allows attackers to inject malicious scripts into discussion pages. When other users view an affected page, the injected script executes in their browser, potentially enabling account hijacking, session theft, or defacement of the wiki platform.

Vendors: Wikimedia Foundation.

Quick answers

Is CVE-2026-100238 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100238 being exploited in the wild.
How severe is CVE-2026-100238?: Informational severity, published 29 September 2026.
Which products and versions are affected?: Wikimedia Foundation Mediawiki Flow Extension before 1.46.1, 1.45.5, 1.43.10.
Is there a fix for CVE-2026-100238?: 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-2026-100238 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-100238?: Check whether you run Wikimedia Foundation Mediawiki Flow Extension 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 stored XSS vulnerability in the Mediawiki Flow extension allows injection of unsanitized input into web page generation. The vulnerability affects versions before 1.46.1, 1.45.5, and 1.43.10, where user-supplied content in discussion threads is not properly neutralized before being rendered. An attacker can craft malicious discussion posts containing JavaScript that persists in the database and executes in the browsers of all users who view the affected thread.

Affected products

Wikimedia Foundation Mediawiki Flow Extension before 1.46.1, 1.45.5, 1.43.10

Timeline

2026-09-29: disclosed

References

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