---
id: "CVE-2026-114370"
kind: "vulnerability"
aliases: ["CVE-2026-114370"]
title: "Undertow: symlink check lets static file requests reach sibling directories"
severity: "low"
cvss: 3.7
epss: 0.00323
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["java", "runtime", "self-hosted", "undertow"]
not_affected_if: ["no-static-file-serving", "no-symlinks-in-served-dirs"]
published_at: "2026-10-21T16:17:33+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T04:43:32+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114370", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114370", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# Undertow: symlink check lets static file requests reach sibling directories

Undertow's PathResourceManager, which serves static files, checks symbolic link targets by string prefix rather than full directory name. An attacker can read files in a sibling directory whose name starts with the same characters as an allowed directory.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114370
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114370

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_