Flask-Cors Directory Traversal vulnerability
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | flask-cors | < 3.0.9 | 3.0.9 |
References
- https://github.com/corydolphin/flask-cors/releases/tag/3.0.9
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00028.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00032.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00039.html
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00048.html
- https://www.debian.org/security/2020/dsa-4775
- https://github.com/advisories/GHSA-xc3p-ff3m-f46v
- https://nvd.nist.gov/vuln/detail/CVE-2020-25032
- https://github.com/corydolphin/flask-cors/commit/67c4b2cc98ae87cf1fa7df4f97fd81b40c79b895
- https://github.com/corydolphin/flask-cors
- https://github.com/pypa/advisory-database/tree/main/vulns/flask-cors/PYSEC-2020-43.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-22- Platform
- Python (PyPI)
- Package
flask-cors- Disclosed
- 31.08.2020
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2020-43 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-xc3p-ff3m-f46v - 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
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Flask-Cors Directory Traversal vulnerability this entry
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