CVE-2021-3733

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. 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. The greatest threat that this flaw poses is to application availability.

6.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

4.0 /10

CVSS v2.0 : MEDIUM

V2 Legend

Vector : AV:N/AC:L/Au:S/C:N/I:N/A:P

Exploitability : 8.0 / Impact : 2.9

Access Vector NETWORK

Access Complexity LOW

Authentication SINGLE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact PARTIAL

References
Link Resource
https://bugs.python.org/issue43075 Exploit Issue Tracking Patch Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1995234 Issue Tracking Third Party Advisory
https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb Patch Third Party Advisory
https://github.com/python/cpython/pull/24391 Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
https://security.netapp.com/advisory/ntap-20220407-0001/ Third Party Advisory
https://ubuntu.com/security/CVE-2021-3733 Patch Third Party Advisory
https://bugs.python.org/issue43075 Exploit Issue Tracking Patch Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1995234 Issue Tracking Third Party Advisory
https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb Patch Third Party Advisory
https://github.com/python/cpython/pull/24391 Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
https://security.netapp.com/advisory/ntap-20220407-0001/ Third Party Advisory
https://ubuntu.com/security/CVE-2021-3733 Patch Third Party Advisory
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.10.0:-:*:*:*:*:*:*

Configuration 2 (hide)

OR cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:*
cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
cpe:2.3:a:redhat:codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*

Configuration 3 (hide)

OR cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*

Configuration 4 (hide)

OR cpe:2.3:a:netapp:management_services_for_element_software_and_netapp_hci:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:solidfire\,_enterprise_sds_\&_hci_storage_node:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*
History

03 Nov 2025, 22:15

Type Values Removed Values Added
References
  • () https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html -

21 Nov 2024, 06:22

Type Values Removed Values Added
References () https://bugs.python.org/issue43075 - Exploit, Issue Tracking, Patch, Vendor Advisory () https://bugs.python.org/issue43075 - Exploit, Issue Tracking, Patch, Vendor Advisory
References () https://bugzilla.redhat.com/show_bug.cgi?id=1995234 - Issue Tracking, Third Party Advisory () https://bugzilla.redhat.com/show_bug.cgi?id=1995234 - Issue Tracking, Third Party Advisory
References () https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb - Patch, Third Party Advisory () https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb - Patch, Third Party Advisory
References () https://github.com/python/cpython/pull/24391 - Patch, Third Party Advisory () https://github.com/python/cpython/pull/24391 - Patch, Third Party Advisory
References () https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html - () https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html -
References () https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html - () https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html -
References () https://security.netapp.com/advisory/ntap-20220407-0001/ - Third Party Advisory () https://security.netapp.com/advisory/ntap-20220407-0001/ - Third Party Advisory
References () https://ubuntu.com/security/CVE-2021-3733 - Patch, Third Party Advisory () https://ubuntu.com/security/CVE-2021-3733 - Patch, Third Party Advisory

30 Jun 2023, 23:15

Type Values Removed Values Added
References
  • (MLIST) https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html -

24 May 2023, 21:15

Type Values Removed Values Added
References
  • (MLIST) https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html -

26 Oct 2022, 13:35

Type Values Removed Values Added
CPE cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_server:8.0:*:*:*:*:*:*:* cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:*

14 Jun 2022, 14:38

Type Values Removed Values Added
CPE cpe:2.3:a:fedoraproject:fedora_extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:* cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*

01 Jun 2022, 20:30

Type Values Removed Values Added
CPE cpe:2.3:a:python:python:3.7.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.9.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.6.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.8.0:-:*:*:*:*:*:*		 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:a:netapp:management_services_for_element_software_and_netapp_hci:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:solidfire\,_enterprise_sds_\&_hci_storage_node:-:*:*:*:*:*:*:*
cpe:2.3:a:fedoraproject:fedora_extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*
cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*
cpe:2.3:a:redhat:codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*
cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_server:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*
cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
References (CONFIRM) https://security.netapp.com/advisory/ntap-20220407-0001/ - (CONFIRM) https://security.netapp.com/advisory/ntap-20220407-0001/ - Third Party Advisory
References (MISC) https://ubuntu.com/security/CVE-2021-3733 - Third Party Advisory (MISC) https://ubuntu.com/security/CVE-2021-3733 - Patch, Third Party Advisory

08 Apr 2022, 00:15

Type Values Removed Values Added
References
  • (CONFIRM) https://security.netapp.com/advisory/ntap-20220407-0001/ -

14 Mar 2022, 23:55

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown 		v2 : 4.0
v3 : 6.5
CPE cpe:2.3:a:python:python:3.9.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.6.0:-:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.7.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.8.0:-:*:*:*:*:*:*
cpe:2.3:a:python:python:3.10.0:-:*:*:*:*:*:*
References (MISC) https://bugs.python.org/issue43075 - (MISC) https://bugs.python.org/issue43075 - Exploit, Issue Tracking, Patch, Vendor Advisory
References (MISC) https://ubuntu.com/security/CVE-2021-3733 - (MISC) https://ubuntu.com/security/CVE-2021-3733 - Third Party Advisory
References (MISC) https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb - (MISC) https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb - Patch, Third Party Advisory
References (MISC) https://bugzilla.redhat.com/show_bug.cgi?id=1995234 - (MISC) https://bugzilla.redhat.com/show_bug.cgi?id=1995234 - Issue Tracking, Third Party Advisory
References (MISC) https://github.com/python/cpython/pull/24391 - (MISC) https://github.com/python/cpython/pull/24391 - Patch, Third Party Advisory
CWE CWE-400

10 Mar 2022, 17:54

Type Values Removed Values Added
New CVE
Information

Published : 2022-03-10 17:42

Updated : 2025-11-03 22:15

NVD link : CVE-2021-3733

Mitre link : CVE-2021-3733

CVE.ORG link : CVE-2021-3733

JSON object : View

Products Affected

redhat

  • enterprise_linux_for_ibm_z_systems
  • enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions
  • codeready_linux_builder_for_power_little_endian
  • enterprise_linux_eus
  • enterprise_linux
  • codeready_linux_builder_for_ibm_z_systems
  • enterprise_linux_for_ibm_z_systems_eus
  • enterprise_linux_server_tus
  • codeready_linux_builder
  • enterprise_linux_server_update_services_for_sap_solutions
  • enterprise_linux_for_power_little_endian
  • enterprise_linux_server_aus
  • enterprise_linux_for_power_little_endian_eus

fedoraproject

  • fedora
  • extra_packages_for_enterprise_linux

netapp

  • solidfire\,_enterprise_sds_\&_hci_storage_node
  • hci_compute_node_firmware
  • management_services_for_element_software_and_netapp_hci
  • ontap_select_deploy_administration_utility

python

  • python
CWE
CWE-400

Uncontrolled Resource Consumption