CVE-2021-32838
Regular Expression Denial of Service in flask-restx
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Regular Expression Denial of Service in flask-restx
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.
- Record
CVE-2021-32838- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2021-0085
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.
- Record
EUVD-2021-0085- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-3q6g-vf58-7m4g
Regular Expression Denial of Service in flask-restx
Flask RESTX contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in email_regex.
- Record
GHSA-3q6g-vf58-7m4g- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400, CWE-1333
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-32838- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-32838- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-3q6g-vf58-7m4g
Regular Expression Denial of Service in flask-restx
Flask RESTX contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service) in email_regex.
- Record
GHSA-3q6g-vf58-7m4g- CVSS 4.0
- 8.7 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-1333, CWE-400
- Updated
- 2026-11-02
OSVMGASA-2021-0473 No score
Updated python-flask-restx packages fix security vulnerability
Regular expression denial of service in email_regex.
- Record
MGASA-2021-0473- Updated
- 2026-11-02
OSVPYSEC-2021-325 No score
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.
- Record
PYSEC-2021-325- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
flask-restxPyPI |
before 0.5.1 | 0.5.1 |
flask-restxPyPI |
before 0.5.1, plus listed versions 0.0.1.dev00.1.00.1.10.2.00.3.00.4.00.5.0 |
0.5.1 |
python-flask-restxMageia:8 |
before 0.5.1-1.mga8 | 0.5.1-1.mga8 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32838 is a high vulnerability (CVSS 7.5) in Flask-restx Project Flask-restx, published September 8, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.86%, the 79th percentile. Fixed in flask-restx 0.5.1.
References
github.com/advisories/GHSA-3q6g-vf58-7m4g
pypi.org/project/flask-restx
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5UCTFVDU3677B5OBGK4EF5NMUPJLL6SQ
Show 11 moreShow less
nvd.nist.gov/vuln/detail/CVE-2021-32838
advisories.mageia.org/MGASA-2021-0473.html
bugs.mageia.org/show_bug.cgi?id=29509