CVE-2026-114370: Undertow: undertow: pathresourcemanager safepaths check allows sibling-directory symlink traversal

Vulnerability summary

CVE-2026-114370 is a low (CVSS 3.7) vulnerability in undertow. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 25.3% of scored vulnerabilities.

Timeline

1. 21-10-2026
   PublishedVulnerability first disclosed.
2. 03-11-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in the PathResourceManager component of the Undertow web server. This component is responsible for serving static files from the file system. The issue occurs because the mechanism used to verify if a symbolic link points to a safe location only checks if the target path starts with a specific string, without ensuring it matches a full directory name. This could allow an attacker to access files in a sibling directory if that directorys name starts with the same characters as an authorized safe directory.

• CWE-22Improper Limitation of a Pathname to a Restricted DirectoryThe product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.