CVE-2025-62698: The Wikimedia Foundation Mediawiki – ExternalGuidance · XSS or 'Cross-site Scripting'
Affects The Wikimedia Foundation Mediawiki – ExternalGuidanceSource CVE Database V5
Not known to be exploited · CVSS 6.9 Medium : upgrade to 1.39 when convenient.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.39
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:LExploitation evidence
Disclosed: evidence found.
CVE published 20 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2026-10-25.
What to do
Upgrade The Wikimedia Foundation Mediawiki – ExternalGuidance to 1.39.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| The Wikimedia Foundation Mediawiki - ExternalGuidance | Affected
| Fixed in
|
AI-suggested
1. Monitor official Wikimedia Foundation channels for the release of a security patch for Mediawiki ExternalGuidance and apply it immediately upon availability. 2. In the interim, disable or restrict the ExternalGuidance extension if feasible to reduce the attack surface. 3. Implement rigorous input validation and output encoding on all user-supplied data within Mediawiki pages, especially those rendered by ExternalGuidance. 4. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 5. Conduct regular security audits and code reviews focusing on input handling in custom Mediawiki extensions or templates. 6. Educate Mediawiki administrators and users about the risks of XSS and encourage vigilance for suspicious content or behavior. 7. Employ web application firewalls (WAFs) with rules designed to detect and block XSS attack patterns targeting Mediawiki. 8. Monitor logs and user reports for signs of exploitation attempts or anomalous script execution. 9. Consider isolating Mediawiki instances or restricting access to trusted networks to limit exposure. 10. Maintain up-to-date backups to enable rapid recovery in case of compromise.
Description
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in The Wikimedia Foundation Mediawiki - ExternalGuidance allows Stored XSS.This issue affects Mediawiki - ExternalGuidance: from master before 1.39.