CVE-2021-3733
python
MEDIUM 6.5
At a glance
- Source
- NVD
- EPSS
- EPSS 4.80 % · percentile 92 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-400 — Uncontrolled Resource Consumption (DoS)
References
- https://bugs.python.org/issue43075
- https://bugzilla.redhat.com/show_bug.cgi?id=1995234
- https://github.com/python/cpython/pull/24391
- https://ubuntu.com/security/CVE-2021-3733
- https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fb
- https://security.netapp.com/advisory/ntap-20220407-0001/
- 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://cert-portal.siemens.com/productcert/html/ssa-398330.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 2.0 | MEDIUM 4.0 | AV:N/AC:L/Au:S/C:N/I:N/A:P | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2021-27010
- GCVE · GCVE-0-2021-3733
CERT-FR advisories
- CERTFR-2026-AVI-0395 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0050 — Multiples vulnérabilités dans les produits Juniper Networks · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0969 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2023-AVI-1015 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
- CERTFR-2023-AVI-0513 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2023-AVI-0214 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2022-AVI-928 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2022-AVI-597 — Multiples vulnérabilités dans IBM Spectrum Protect Plus · cert.ssi.gouv.fr
- CERTFR-2022-AVI-097 — Multiples vulnérabilités dans IBM Spectrum Protect Plus · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*< 3.6.14cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.7.0 < 3.7.11cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.8.0 < 3.8.10cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.9.0 < 3.9.5cpe:2.3:a:python:python:3.10.0:-:*:*:*:*:*:*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:*:*:*:*:*:*:*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:*:*:*:*:*:*:*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:-:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| python | affected Fixed in python v3.6.14, python v3.7.11, python v3.8.10, python v3.9.5. |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |