CVE-2025-11966: Eclipse Foundation Vert.x · XSS or 'Cross-site Scripting'
Affects Eclipse Foundation Vert.xSource CVE Database V5
Not known to be exploited · CVSS 2.3 Low.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 22 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Eclipse Foundation Vert.x | Affected
| Fixed in– |
AI-suggested
To mitigate CVE-2025-11966, European organizations should first assess whether directory listing is enabled in their Vert.x deployments. If directory listing is not essential, it should be disabled to eliminate the attack surface. Where directory listing is required, organizations must implement strict input validation and output encoding on file and directory names before rendering them in HTML attributes. This includes escaping characters that could be interpreted as HTML or JavaScript, such as <, >, &, ', and ". Applying a Content Security Policy (CSP) that restricts script execution can further reduce the impact of any injected scripts. Regularly updating Vert.x to versions beyond 5.0.4, once patched releases are available, is critical. Monitoring file system changes and restricting file creation or renaming permissions to trusted users can reduce the risk of attacker-controlled filenames. Finally, conducting security reviews and penetration testing focused on web interface vulnerabilities will help identify residual risks.
Description
In Eclipse Vert.x versions [4.0.0, 4.5.21] and [5.0.0, 5.0.4], when "directory listing" is enabled, file and directory names are inserted into generated HTML without proper escaping in the href, title, and link attributes. An attacker who can create or rename files or directories within a served path can craft filenames containing malicious script or HTML content, leading to stored cross-site scripting (XSS) that executes in the context of users viewing the affected directory listing.