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VulnerabilityPublished Updated

CVE-2025-53500: Wikimedia Foundation Mediawiki – MassEditRegex Extension · XSS or 'Cross-site Scripting'

Affects Wikimedia Foundation Mediawiki – MassEditRegex ExtensionSource CVE Database V5

0

Not known to be exploited · CVSS 5.6 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score
5.6Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHubwikimedia/mediawiki/extensions/MassEditRegexpkg:github/wikimedia/mediawiki/extensions/MassEditRegexOther threatsAffected
  • 1.39.0 – 1.44.0
5 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should promptly upgrade the MassEditRegex extension to the fixed versions: 1.39.12 or later for the 1.39.x branch, 1.42.7 or later for the 1.42.x branch, and 1.43.2 or later for the 1.43.x branch. In the absence of immediate patching, administrators should consider disabling the MassEditRegex extension temporarily to eliminate the attack surface. Implement strict Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on wiki pages. Conduct thorough input validation and output encoding on any user-generated content, especially where batch editing features are used. Regularly audit wiki pages for suspicious scripts or injected content. Additionally, monitor logs for unusual activity related to the MassEditRegex extension and educate users on recognizing potential phishing or session hijacking attempts stemming from XSS attacks.

Description

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - MassEditRegex Extension allows Stored XSS.This issue affects Mediawiki - MassEditRegex Extension: from 1.39.X before 1.39.12, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.

References

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