CVE-2021-3733
MEDIUM6.5EPSS 0.63%python3.5 - security update
Published: 3/10/2022Modified: 4/28/2026
Description
There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.
Affected packages (7)
- Bitnami/libpythonfrom 0, < 3.6.14, >= 3.7.0, < 3.7.11, >= 3.8.0, < 3.8.10, >= 3.9.0, < 3.9.5
- Bitnami/pythonfrom 0, < 3.6.14, >= 3.7.0, < 3.7.11, >= 3.8.0, < 3.8.10, >= 3.9.0, < 3.9.5
- Bitnami/python-minfrom 0, < 3.6.14, >= 3.7.0, < 3.7.11, >= 3.8.0, < 3.8.10, >= 3.9.0, < 3.9.5, >= 3.10.0, < 3.10.1
- Debian/pypy3from 0, < 7.3.5+dfsg-2
- Debian/python2.7from 0
- Debian/python3.5from 0, < 3.5.3-1+deb9u5
- Debian/python3.9from 0, < 3.9.2-1+deb11u2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
References (11)
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-3733
- WEBhttps://bugs.python.org/issue43075
- WEBhttps://bugzilla.redhat.com/show_bug.cgi?id=1995234
- WEBhttps://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb
- WEBhttps://github.com/python/cpython/pull/24391
- WEBhttps://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- WEBhttps://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
- WEBhttps://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2021-3733
- WEBhttps://security.netapp.com/advisory/ntap-20220407-0001/
- WEBhttps://ubuntu.com/security/CVE-2021-3733