CVE-2021-3733

python: urllib: Regular expression DoS in AbstractBasicAuthHandler

Severity Score

6.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

Se presenta un fallo en la clase AbstractBasicAuthHandler de urllib. Un atacante que controle un servidor HTTP malicioso al que se conecte un cliente HTTP (como un navegador web), podría desencadenar una Denegación de Servicio por Expresión Regular (ReDOS) durante una petición de autenticación con una carga útil especialmente diseñada que sea enviada por el servidor al cliente. La mayor amenaza que supone este fallo es para la disponibilidad de la aplicación

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

Single

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-08-23 CVE Reserved
2021-09-17 CVE Published
2024-05-29 EPSS Updated
2024-08-03 CVE Updated
2024-08-03 First Exploit
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-400: Uncontrolled Resource Consumption

CAPEC

References (9)

URL	Tag	Source
https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html	Mailing List
https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html	Mailing List
https://security.netapp.com/advisory/ntap-20220407-0001	Third Party Advisory

URL	Date	SRC
https://bugs.python.org/issue43075	2024-08-03

URL	Date	SRC
https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb	2023-06-30
https://github.com/python/cpython/pull/24391	2023-06-30
https://ubuntu.com/security/CVE-2021-3733	2023-06-30

URL	Date	SRC
https://bugzilla.redhat.com/show_bug.cgi?id=1995234	2022-05-10
https://access.redhat.com/security/cve/CVE-2021-3733	2022-05-10

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				< 3.6.14 Search vendor "Python" for product "Python" and version " < 3.6.14"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				>= 3.7.0 < 3.7.11 Search vendor "Python" for product "Python" and version " >= 3.7.0 < 3.7.11"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				>= 3.8.0 < 3.8.10 Search vendor "Python" for product "Python" and version " >= 3.8.0 < 3.8.10"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				>= 3.9.0 < 3.9.5 Search vendor "Python" for product "Python" and version " >= 3.9.0 < 3.9.5"		-		Affected
Python Search vendor "Python"		Python Search vendor "Python" for product "Python"				3.10.0 Search vendor "Python" for product "Python" and version "3.10.0"		-		Affected
Redhat Search vendor "Redhat"		Codeready Linux Builder Search vendor "Redhat" for product "Codeready Linux Builder"				8.0 Search vendor "Redhat" for product "Codeready Linux Builder" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Codeready Linux Builder For Ibm Z Systems Search vendor "Redhat" for product "Codeready Linux Builder For Ibm Z Systems"				8.0 Search vendor "Redhat" for product "Codeready Linux Builder For Ibm Z Systems" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Codeready Linux Builder For Power Little Endian Search vendor "Redhat" for product "Codeready Linux Builder For Power Little Endian"				8.0 Search vendor "Redhat" for product "Codeready Linux Builder For Power Little Endian" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				8.0 Search vendor "Redhat" for product "Enterprise Linux" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Eus Search vendor "Redhat" for product "Enterprise Linux Eus"				8.4 Search vendor "Redhat" for product "Enterprise Linux Eus" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux For Ibm Z Systems Search vendor "Redhat" for product "Enterprise Linux For Ibm Z Systems"				8.0 Search vendor "Redhat" for product "Enterprise Linux For Ibm Z Systems" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux For Ibm Z Systems Eus Search vendor "Redhat" for product "Enterprise Linux For Ibm Z Systems Eus"				8.4 Search vendor "Redhat" for product "Enterprise Linux For Ibm Z Systems Eus" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux For Power Little Endian Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian"				8.0 Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian" and version "8.0"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux For Power Little Endian Eus Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus"				8.4 Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Server Aus Search vendor "Redhat" for product "Enterprise Linux Server Aus"				8.4 Search vendor "Redhat" for product "Enterprise Linux Server Aus" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions"				8.4 Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Server Tus Search vendor "Redhat" for product "Enterprise Linux Server Tus"				8.4 Search vendor "Redhat" for product "Enterprise Linux Server Tus" and version "8.4"		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Server Update Services For Sap Solutions Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions"				8.4 Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions" and version "8.4"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Extra Packages For Enterprise Linux Search vendor "Fedoraproject" for product "Extra Packages For Enterprise Linux"				7.0 Search vendor "Fedoraproject" for product "Extra Packages For Enterprise Linux" and version "7.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				35 Search vendor "Fedoraproject" for product "Fedora" and version "35"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				36 Search vendor "Fedoraproject" for product "Fedora" and version "36"		-		Affected
Netapp Search vendor "Netapp"		Management Services For Element Software And Netapp Hci Search vendor "Netapp" for product "Management Services For Element Software And Netapp Hci"				-		-		Affected
Netapp Search vendor "Netapp"		Ontap Select Deploy Administration Utility Search vendor "Netapp" for product "Ontap Select Deploy Administration Utility"				-		-		Affected
Netapp Search vendor "Netapp"		Solidfire\, Enterprise Sds \& Hci Storage Node Search vendor "Netapp" for product "Solidfire\, Enterprise Sds \& Hci Storage Node"				-		-		Affected
Netapp Search vendor "Netapp"		Hci Compute Node Firmware Search vendor "Netapp" for product "Hci Compute Node Firmware"				-		-		Affected