# CVE-2026-34151

## Summary

- **CVE ID:** CVE-2026-34151
- **Severity:** HIGH
- **CVSS Score:** 8.2 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-24
- **Published:** Sep 14, 2026
- **Last Modified:** Sep 14, 2026

## Description

XWiki Platform is a generic wiki platform. Prior to 17.10.5 and 18.2.0, the /skin/ action in com.xpn.xwiki.web.SkinAction can resolve double-encoded parent-directory segments outside the intended skin or web-application resource prefix when Jetty 12 or later decodes the request path. The affected lookup is replaced with Environment.getResourceAsStream(String, String), which constrains a resource to its expected prefix. An unauthenticated remote attacker can use the vulnerable behavior to read arbitrary resources permitted to the Jetty process, including WEB-INF/xwiki.cfg and, depending on deployment depth and operating-system permissions, host files. Tomcat and Jetty versions before 12 do not appear affected. This issue is fixed in versions 17.10.5 and 18.2.0.

## Affected Products

- xwiki — xwiki-platform (< 17.10.5)
- xwiki — xwiki-platform (>= 18.0.0-rc-1, < 18.2.0)

## References

- [CNA](https://github.com/xwiki/xwiki-platform/security/advisories/GHSA-qj4x-9g63-25g6)
- [CNA](https://github.com/xwiki/xwiki-commons/pull/1675)
- [CNA](https://github.com/xwiki/xwiki-platform/commit/79eba8655f3a96021a8e7ad07956e48d20a82383)
- [CNA](https://github.com/xwiki/xwiki-platform/commit/f7b33704083d3b4e45d1b9fc1e2cc33c66855f85)
- [CNA](https://github.com/xwiki/xwiki-platform/releases/tag/xwiki-platform-17.10.5)
- [CNA](https://github.com/xwiki/xwiki-platform/releases/tag/xwiki-platform-18.2.0)
- [CNA](https://jira.xwiki.org/browse/XCOMMONS-3594)
- [CNA](https://jira.xwiki.org/browse/XWIKI-24075)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.54%
- **EPSS Percentile:** 44.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._