Flask-CORS vulnerable to Improper Handling of Case Sensitivity
corydolphin/flask-cors version 5.0.1 contains a vulnerability where the request path matching is case-insensitive due to the use of the try_match function, which is originally intended for matching hosts. This results in a mismatch because paths in URLs are case-sensitive, but the regex matching treats them as case-insensitive. This misconfiguration can lead to significant security vulnerabilities, allowing unauthorized origins to access paths meant to be restricted, resulting in data exposure and potential data leaks.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | flask-cors | < 6.0.0 | 6.0.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2024-6866
- https://github.com/corydolphin/flask-cors/commit/eb39516a3c96b90d0ae5f51293972395ec3ef358
- https://github.com/corydolphin/flask-cors
- https://github.com/corydolphin/flask-cors/blob/4.0.1/flask_cors/extension.py#L195
- https://huntr.com/bounties/808c11af-faee-43a8-824b-b5ab4f62b9e6
- https://lists.debian.org/debian-lts-announce/2025/05/msg00049.html
- https://pypi.org/project/flask-cors
- https://github.com/advisories/GHSA-43qf-4rqw-9q2g
- CVSS vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-178- Platform
- Python (PyPI)
- Package
flask-cors- Disclosed
- 20.03.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1383 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-43qf-4rqw-9q2g - CC BY 4.0
Vulnerability history: flask-cors
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 08.2020 03.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 4
Disclosures per year
- 2020: 1
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 2
- 2025: 3
- 2026: 0
-
Flask-CORS vulnerable to Improper Handling of Case Sensitivity this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.