---
id: CVE-2020-25032
aliases:
  - GHSA-xc3p-ff3m-f46v
  - PYSEC-2020-43
title: Flask-Cors Directory Traversal vulnerability
summary: Flask-Cors Directory Traversal vulnerability
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
vendor: flask-cors
product: flask-cors
ecosystem: pip
affected:
  - flask-cors < 3.0.9
patched:
  - flask-cors 3.0.9
published: '2021-05-06'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:49:15.088799664Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-xc3p-ff3m-f46v'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2020-25032'
  - url: >-
      https://github.com/corydolphin/flask-cors/commit/67c4b2cc98ae87cf1fa7df4f97fd81b40c79b895
  - url: 'https://github.com/advisories/GHSA-xc3p-ff3m-f46v'
  - url: 'https://github.com/corydolphin/flask-cors'
  - url: 'https://github.com/corydolphin/flask-cors/releases/tag/3.0.9'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/flask-cors/PYSEC-2020-43.yaml
  - url: 'https://www.debian.org/security/2020/dsa-4775'
  - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00028.html'
  - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00032.html'
  - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00039.html'
  - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00048.html'
tags:
  - osv
  - pip
epss: 0.04017
epssPercentile: 0.90181
ingestedAt: '2026-09-12T03:13:01.739Z'
---

## Overview

An issue was discovered in Flask-CORS (aka CORS Middleware for Flask) before 3.0.9. It allows `../` directory traversal to access private resources because resource matching does not ensure that pathnames are in a canonical format.

## Affected packages

- `flask-cors < 3.0.9`

## Remediation

Upgrade to a patched release:

- `flask-cors 3.0.9`