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TI-2021-02666 Aliases CVE-2021-3733GHSA-wj55-vqcq-gxcp

Uncontrolled resource consumption in python

Priority MEDIUM 43CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 9 fixed, 3 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-400.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.04799 91st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 6 advisoriesRed Hat: 9 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
—pythonFixed in python v3.6.14, python v3.7.11, python v3.8.10, python v3.9.5.—No fix listedCNA
  • python Vendor— Affected Fixed in python v3.6.14, python v3.7.11, python v3.8.10, python v3.9.5. Fixed in — No fix listed CNA

CPE configurations NVD · 24

CPEVersionsRoleVendor
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*before 3.6.14; 3.7.0 to before 3.7.11; 3.8.0 to before 3.8.10; 3.9.0 to before 3.9.5Vulnerablepython-pillow
cpe:2.3:a:python:python:3.10.0:-:*:*:*:*:*:*3.10.0Vulnerablepython-pillow
cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:a:redhat:codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
  • cpe:2.3:a:python:python:*:*:*:*:*:*:*:* Versions before 3.6.14; 3.7.0 to before 3.7.11; 3.8.0 to before 3.8.10; 3.9.0 to before 3.9.5 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.10.0:-:*:*:*:*:*:* Versions 3.10.0 Vulnerable ·python-pillow
  • cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:a:redhat:codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_eus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
Show 14 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:*8.4VulnerableRed Hat
cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:*7.0VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*34VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*36VulnerableFedoraproject
cpe:2.3:a:netapp:management_services_for_element_software_and_netapp_hci:-:*:*:*:*:*:*:*not specified by NVDVulnerableNetApp
cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*not specified by NVDVulnerableNetApp
cpe:2.3:a:netapp:solidfire\,_enterprise_sds_\&_hci_storage_node:-:*:*:*:*:*:*:*not specified by NVDVulnerableNetApp
cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*not specified by NVDVulnerableNetApp
  • cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_server_aus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_server_tus:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux_server_update_services_for_sap_solutions:8.4:*:*:*:*:*:*:* Versions 8.4 Vulnerable ·Red Hat
  • cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
  • cpe:2.3:a:netapp:management_services_for_element_software_and_netapp_hci:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
  • cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
  • cpe:2.3:a:netapp:solidfire\,_enterprise_sds_\&_hci_storage_node:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
  • cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp

Remediation

Red Hat 6 advisories

  • RHSA-2022:1821 Released 2022-05-10 · Red Hat rating Moderate
    python27:2.7 security update
    • Red Hat Enterprise Linux AppStream (v. 8) Cython-0.28.1-7.module+el8.1.0+3111+de3f2d8e.src::python27:2.7, PyYAML-3.12-16.module+el8.1.0+3111+de3f2d8e.src::python27:2.7, babel-2.5.1-10.module+el8.5.0+11014+88fc0d0b.noarch::python27:2.7 +47
  • RHSA-2022:1764 Released 2022-05-10 · Red Hat rating Moderate
    python38:3.8 and python38-devel:3.8 security update
    • Red Hat Enterprise Linux AppStream (v. 8) Cython-0.29.14-4.module+el8.4.0+8888+89bc7e79.src::python38:3.8, PyYAML-5.4.1-1.module+el8.5.0+10721+14d8e0d5.src::python38:3.8, babel-2.7.0-11.module+el8.5.0+11015+9c1c7c42.src::python38:3.8 +47
    • Red Hat Enterprise Linux CRB (v. 8) pytest-4.6.6-3.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8, python-atomicwrites-1.3.0-8.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8, python-attrs-19.3.0-3.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8 +15
  • RHSA-2022:1663 Released 2022-05-02 · Red Hat rating Moderate
    python27-python and python27-python-pip security update
    • Red Hat Software Collections for RHEL Workstation(v. 7) python27-python-2.7.18-4.el7, python27-python-debug-2.7.18-4.el7, python27-python-devel-2.7.18-4.el7 +4
    • Red Hat Software Collections for RHEL(v. 7) python27-python-2.7.18-4.el7, python27-python-debug-2.7.18-4.el7, python27-python-devel-2.7.18-4.el7 +4
Show 3 more Red Hat advisories
  • RHSA-2021:4160 Released 2021-11-09 · Red Hat rating Moderate
    python39:3.9 and python39-devel:3.9 security update
    • Red Hat CodeReady Linux Builder (v. 8) Cython-0.29.21-5.module+el8.4.0+9822+20bf1249.src::python39-devel:3.9, pybind11-2.6.1-2.module+el8.4.0+9822+20bf1249.src::python39-devel:3.9, pytest-6.0.2-2.module+el8.4.0+9822+20bf1249.src::python39-devel:3.9 +33
    • Red Hat Enterprise Linux AppStream (v. 8) PyYAML-5.4.1-1.module+el8.5.0+10613+59a13ec4.src::python39:3.9, mod_wsgi-4.7.1-4.module+el8.4.0+9822+20bf1249.src::python39:3.9, numpy-1.19.4-3.module+el8.5.0+12204+54860423.src::python39:3.9 +47
  • RHSA-2021:4057 Released 2021-11-02 · Red Hat rating Moderate
    python3 security update
    • Red Hat Enterprise Linux AppStream (v. 8) platform-python-3.6.8-39.el8_4, platform-python-debug-3.6.8-39.el8_4, platform-python-devel-3.6.8-39.el8_4 +3
    • Red Hat Enterprise Linux BaseOS (v. 8) platform-python-3.6.8-39.el8_4, python3-3.6.8-39.el8_4, python3-libs-3.6.8-39.el8_4 +1
  • RHSA-2021:3254 Released 2021-08-24 · Red Hat rating Moderate
    rh-python38 security, bug fix, and enhancement update
    • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-python38-babel-2.7.0-12.el7, rh-python38-python-3.8.11-2.el7, rh-python38-python-babel-2.7.0-12.el7 +14
    • Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-python38-babel-2.7.0-12.el7, rh-python38-python-3.8.11-2.el7, rh-python38-python-babel-2.7.0-12.el7 +14
    • Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-python38-babel-2.7.0-12.el7, rh-python38-python-3.8.11-2.el7, rh-python38-python-babel-2.7.0-12.el7 +14

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2021:4160
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:4057, RHSA-2021:4160, RHSA-2022:1764, RHSA-2022:1821
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2021:4057
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2022:1764
Red Hat Software Collections for RHEL Workstation(v. 7)Fixed RHSA-2022:1663
Red Hat Software Collections for RHEL(v. 7)Fixed RHSA-2022:1663
Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:3254
Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7)Fixed RHSA-2021:3254
Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:3254
Not affected: 2 products
  • Red Hat Software Collections for RHEL Workstation(v. 7)
  • Red Hat Software Collections for RHEL(v. 7)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-3733
  2. 2026-10-03 Alias added: GHSA-wj55-vqcq-gxcp
  3. 2026-10-08 CISA SSVC decision points changed
  4. 2026-10-09 Priority changed: LOW → MEDIUM

References

Exploit 1

Patch 3

Advisory 2

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences