---
id: CVE-2024-49766
aliases:
  - GHSA-f9vj-2wh5-fj8j
  - PYSEC-2026-2045
title: Werkzeug safe_join not safe on Windows
summary: Werkzeug safe_join not safe on Windows
severity: medium
vendor: werkzeug
product: werkzeug
ecosystem: pip
affected:
  - werkzeug < 3.0.6
patched:
  - werkzeug 3.0.6
published: '2024-10-25'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:19.894904779Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-f9vj-2wh5-fj8j'
references:
  - url: >-
      https://github.com/pallets/werkzeug/security/advisories/GHSA-f9vj-2wh5-fj8j
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2024-49766'
  - url: >-
      https://github.com/pallets/werkzeug/commit/2767bcb10a7dd1c297d812cc5e6d11a474c1f092
  - url: 'https://github.com/pallets/werkzeug'
  - url: 'https://github.com/pallets/werkzeug/releases/tag/3.0.6'
  - url: 'https://security.netapp.com/advisory/ntap-20250131-0005'
tags:
  - osv
  - pip
epss: 0.00776
epssPercentile: 0.53927
ingestedAt: '2026-07-08T18:25:48.855Z'
---

## Overview

On Python < 3.11 on Windows, `os.path.isabs()` does not catch UNC paths like `//server/share`. Werkzeug's `safe_join()` relies on this check, and so can produce a path that is not safe, potentially allowing unintended access to data. Applications using Python >= 3.11, or not using Windows, are not vulnerable.

## Affected packages

- `werkzeug < 3.0.6`

## Remediation

Upgrade to a patched release:

- `werkzeug 3.0.6`