CVE-2024-34507Public exploitNetwork attack vector

Cross-site scripting via colliding comment-parser markers

Published May 5, 2024 · Updated Nov 4, 2025

Cross-site scripting in MediaWiki 1.38.0 through 1.39.6, 1.40.0 through 1.40.2, and 1.41.0 allows remote attackers to run script. CommentParser uses ESC-prefixed numeric placeholders while formatting edit summaries, so crafted text can trigger marker replacement inside an anchor attribute and escape its quoted HTML context. Exploitation requires a victim to load the crafted RecentChanges fragment; successful script execution can read data available to that browser session.

CVSS severity7.4
High
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in MediaWiki 1.38.0 through 1.39.6, 1.40.0 through 1.40.2, and 1.41.0 allows remote attackers to run script. CommentParser uses ESC-prefixed numeric placeholders while formatting edit summaries, so crafted text can trigger marker replacement inside an anchor attribute and escape its quoted HTML context. Exploitation requires a victim to load the crafted RecentChanges fragment; successful script execution can read data available to that browser session.

The record

CVE
CVE-2024-34507
Published
May 5, 2024
Updated
Nov 4, 2025
Vendor
Wikimedia Foundation
Product
MediaWiki
Classifications
CWE-80, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=-

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wikimedia Foundation · MediaWikiversion=-

Published CVSS scores

7.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A: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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1203Exploitation for Client Execution

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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