Regular Expression Denial of Service in flask-restx
Priority LOW 37CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-400.
Summary
Flask-RESTX (pypi package flask-restx) is a community driven fork of Flask-RESTPlus. Flask-RESTX before version 0.5.1 is vulnerable to ReDoS (Regular Expression Denial of Service) in email_regex. This is fixed in version 0.5.1.
Why it matters now
EPSS 0.01864 79th percentileScored 2026-11-07
Fix Fixed flask-restx (python-restx): 0.5.1flask-restx (PyPI): 0.5.1
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| python-restx | flask-restx | before 0.5.1 | 0.5.1 | Patch available | CNA |
| — | flask-restx (PyPI) | before 0.5.1 | 0.5.1 | Patch available | GHSA-3q6g-vf58-7m4g |
- flask-restx Vendorpython-restx Affected before 0.5.1 Fixed in 0.5.1 Patch available CNA
- flask-restx (PyPI) Vendor— Affected before 0.5.1 Fixed in 0.5.1 Patch available GHSA-3q6g-vf58-7m4g
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:flask-restx_project:flask-restx:*:*:*:*:*:python:*:* | before 0.5.1 | Vulnerable | Flask-restx Project |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
- cpe:2.3:a:flask-restx_project:flask-restx:*:*:*:*:*:python:*:* Versions before 0.5.1 Vulnerable ·Flask-restx Project
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
Remediation
- Fix · CNA flask-restx (python-restx) Fixed in 0.5.1
- Fix · GHSA-3q6g-vf58-7m4g flask-restx (PyPI) Fixed in 0.5.1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-32838
- 2026-10-03 Alias added: GHSA-3q6g-vf58-7m4g
References
Patch 3
Advisory 5
Other 6
- https://github.com/python-restx/flask-restx/security/advisories/GHSA-3q6g-vf58-7m4g
- https://github.com/pypa/advisory-database/tree/main/vulns/flask-restx/PYSEC-2021-325.yaml
- https://github.com/python-restx/flask-restx
- https://lists.fedoraproject.org/archives/list/[email protected]/message/5UCTFVDU3677B5OBGK4EF5NMUPJLL6SQ
- https://lists.fedoraproject.org/archives/list/[email protected]/message/QUD6SWZLX52AAZUHDETJ2CDMQGEPGFL3
- https://pypi.org/project/flask-restx
Sources
- CVE-2021-32838 · CVE Program
- CVE-2021-32838 · NVD
- FIRST EPSS
- GHSA-3q6g-vf58-7m4g · GitHub Advisory Database · CC BY 4.0
- CVE-2021-32838 · Red Hat security data · CC BY 4.0
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