PyPi: Python

CVE-2021-3733

Safety vulnerability ID: 45815

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Mar 10, 2022 Updated at Nov 29, 2024
Scan your Python projects for vulnerabilities →

Advisory

Python versions 3.6.14, 3.7.11, 3.8.10, 3.9.5 and 3.10.0 include a fix for CVE-2021-3733: 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.
https://python-security.readthedocs.io/vuln/urllib-basic-auth-regex2.html

Affected package

python

Latest version: 0.9.8

Affected versions

Fixed versions

Vulnerability changelog

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. See CVE-2021-3733.


MISC:https://bugs.python.org/issue43075: https://bugs.python.org/issue43075
MISC:https://bugzilla.redhat.com/show_bug.cgi?id=1995234: https://bugzilla.redhat.com/show_bug.cgi?id=1995234
MISC:https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb: https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb
MISC:https://github.com/python/cpython/pull/24391: https://github.com/python/cpython/pull/24391
MISC:https://ubuntu.com/security/CVE-2021-3733: https://ubuntu.com/security/CVE-2021-3733

Resources

Use this package?

Scan your Python project for dependency vulnerabilities in two minutes

Scan your application

Severity Details

CVSS Base Score

MEDIUM 6.5

CVSS v3 Details

MEDIUM 6.5
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
LOW
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Availability (A)
HIGH

CVSS v2 Details

MEDIUM 4.0
Access Vector (AV)
NETWORK
Access Complexity (AC)
LOW
Authentication (Au)
SINGLE
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Impact (A)
PARTIAL