CVE-2021-3733 Information

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb https://ubuntu.com/security/CVE-2021-3733 https://bugs.python.org/issue43075 https://bugzilla.redhat.com/show_bug.cgi?id=1995234 https://github.com/python/cpython/pull/24391 https://security.netapp.com/advisory/ntap-20220407-0001/ 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.

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

6.5