Is CVE-2026-39841 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-39841 being exploited in the wild.

How severe is CVE-2026-39841?

Medium severity, with a CVSS score of 6.1, published 7 April 2026.

Which products and versions are affected?

Wikimedia Foundation Cargo Extension before 3.8.7.

Is there a fix for CVE-2026-39841?

A patch was published on 2026-02-09: Fix merged into master branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-39841 attacked?

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

Am I affected by CVE-2026-39841?

Check whether you run Wikimedia Foundation Cargo 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-2026-39841: Wikimedia MediaWiki Cargo Extension stored XSS in list fields

CVE-2026-39841 · Severity: medium · CVSS 6.1 · Published 2026-04-07

A security vulnerability exists in the Cargo extension for MediaWiki, a tool used to store and query data within wiki pages. An attacker can inject malicious scripts into certain data fields, which are then executed in the browsers of other users who view specific administrative or data-summary pages. This could lead to unauthorized actions being performed on behalf of users or the theft of sensitive session information.

Technologies: Wikimedia Foundation Cargo Extension. Vendors: Wikimedia Foundation.

Quick answers

Is CVE-2026-39841 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-39841 being exploited in the wild.
How severe is CVE-2026-39841?: Medium severity, with a CVSS score of 6.1, published 7 April 2026.
Which products and versions are affected?: Wikimedia Foundation Cargo Extension before 3.8.7.
Is there a fix for CVE-2026-39841?: A patch was published on 2026-02-09: Fix merged into master branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-39841 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-39841?: Check whether you run Wikimedia Foundation Cargo 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 cross-site scripting (XSS) vulnerability exists in the Cargo extension for MediaWiki due to improper neutralization of script-related HTML tags in list fields. The root cause is located in the CargoQueryDisplayer component, where individual items within a list field are not properly encoded before being displayed on pages such as Special:CargoTables and action=pagevalues. An attacker can exploit this by storing arbitrary HTML/JavaScript in a Cargo table's list field (e.g., via a template). When a victim views the affected administrative pages, the malicious script executes in their browser context. The issue is fixed in version 3.8.7.

Affected products

Wikimedia Foundation MediaWiki - Cargo Extension before 3.8.7

Timeline

2026-02-03: disclosed: Vulnerability reported via Phabricator task T416389
2026-02-09: patched: Fix merged into master branch
2026-04-07: advisory: CVE-2026-39841 published

References

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