Stored XSS through Cargo's map format

published 2026-07-01 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-40901

cvss: 5.4; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits: 0; none known

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in The Wikimedia Foundation Mediawiki - Cargo Extension allows Stored XSS.

This issue affects Mediawiki - Cargo Extension: from * before 3.9.1.

Patch / fix

fixed in 1

The Wikimedia Foundation Mediawiki - Cargo Extension 3.9.1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-07-01)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

phabricator.wikimedia.org https://phabricator.wikimedia.org/T424140 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:A
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected products

The Wikimedia Foundation Mediawiki - Cargo Extension

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

phabricator.wikimedia.org /T424140
exploit, issue-tracking
gerrit.wikimedia.org /r/c/mediawiki/extensions/Cargo/+/1277612
issue-tracking

Sources

CVE List CVE-2026-58519
NVD CVE-2026-58519

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary