What is CVE-2026-39840?

CVE-2026-39840 is a medium-severity vulnerability in MediaWiki Cargo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-07.

How severe is CVE-2026-39840?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in MediaWiki Cargo

CVE-2026-39840

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation Mediawiki - Cargo Extension allows XSS Targeting Non-Script Elements.This issue affects Mediawiki - Cargo Extension: before 3.8.7.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (5.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Mediawiki Cargo
Wikimedia Foundation Mediawiki - Cargo Extension — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

c4f26cc8-17ff-4c99-b5e2-38fc1793eacc (Exploit, Issue Tracking, Vendor Advisory)
c4f26cc8-17ff-4c99-b5e2-38fc1793eacc (Patch)

Frequently asked questions

What is CVE-2026-39840?: CVE-2026-39840 is a medium-severity vulnerability in MediaWiki Cargo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-07.
How severe is CVE-2026-39840?: Medium severity. CVSS v3 base score is 6.1 out of 10.