CVE-2026-58031Network attack vector

Stored XSS via unescaped deprecated-module message

Published Jul 1, 2026 · Updated Jul 1, 2026

Stored XSS in Wikimedia Foundation MediaWiki 1.46.0-rc.0 allows remote authenticated users to run script in another user's browser. ApiSandboxLayout renders attacker-controlled stored interface-message content as HTML when a deprecated API module is selected instead of neutralizing markup. Exploitation requires permission to alter the relevant interface message and user interaction with the deprecated module; the script runs in the viewer's session.

CVSS severity5.4
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Wikimedia Foundation MediaWiki 1.46.0-rc.0 allows remote authenticated users to run script in another user's browser. ApiSandboxLayout renders attacker-controlled stored interface-message content as HTML when a deprecated API module is selected instead of neutralizing markup. Exploitation requires permission to alter the relevant interface message and user interaction with the deprecated module; the script runs in the viewer's session.

The record

CVE
CVE-2026-58031
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
Wikimedia Foundation
Product
MediaWiki
Classifications
CWE-79, CAPEC-63, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.46.0-rc.0 <1.46.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wikimedia Foundation · MediaWikiversion=1.46.0-rc.0 <1.46.0

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
0.0Wikimedia FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-63Cross-Site Scripting (XSS)
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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