CVE-2025-61638Public exploitNetwork attack vector

Stored XSS via malformed data attribute names

Published Feb 2, 2026 · Updated Feb 2, 2026

Stored cross-site scripting in Wikimedia Foundation MediaWiki and Parsoid allows remote authenticated users to run script in viewers' browsers. Parser-function and transclusion argument handling treats names such as data-/onclick as HTML attributes, while Sanitizer::validateAttributes exempts data- names from normal cleanup. An attacker needs page-editing rights, and a viewer must preview or open the crafted content and interact with the injected element; script then executes in the viewer's wiki origin.

CVSS severity4.8
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Wikimedia Foundation MediaWiki and Parsoid allows remote authenticated users to run script in viewers' browsers. Parser-function and transclusion argument handling treats names such as data-/onclick as HTML attributes, while Sanitizer::validateAttributes exempts data- names from normal cleanup. An attacker needs page-editing rights, and a viewer must preview or open the crafted content and interact with the injected element; script then executes in the viewer's wiki origin.

The record

CVE
CVE-2025-61638
Published
Feb 2, 2026
Updated
Feb 2, 2026
Vendor
Wikimedia Foundation
Product
Parsoid
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 2, 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=* <0.16.6, 0.20.4, 0.21.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Wikimedia Foundation · Parsoidversion=* <0.16.6, 0.20.4, 0.21.1
Wikimedia Foundation · MediaWikiversion=* <1.39.14, 1.43.4, 1.44.1

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
0.0Wikimedia FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N/E:U

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.

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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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

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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