CVE-2021-3737
A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite
02 Description
A flaw was found in python. An improperly handled HTTP response in the HTTP client code of python may allow a remote attacker, who controls the HTTP server, to make the client script enter an infinite
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 13.16% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 96.3% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-10-14.
- Red Hat severity
- Low. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2022-03-04 00:00Z4 YR AGO
- Last updated
- 2026-10-14 09:49Z15 DAYS AGO
- Reserved
- 2021-08-26
- Assigning CNA
- redhat
- Record state
- PUBLISHED
- Severity
- High (CVSS 7.5)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- Data version
- 5.2
- Document digest
- 864d5eb12ad7b6b61e527c8a48f79326d8dfec9de50e41667fb9898d9cacc8bd
05 Affected products
06 References
- bugs.python.orghttps://bugs.python.org/issue44022
- github.comhttps://github.com/python/cpython/pull/25916
- bugzilla.redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=1995162
- github.comhttps://github.com/python/cpython/pull/26503
- ubuntu.comhttps://ubuntu.com/security/CVE-2021-3737
- www.oracle.comhttps://www.oracle.com/security-alerts/cpujul2022.html
- python-security.readthedocs.iohttps://python-security.readthedocs.io/vuln/urllib-100-continue-loop.html
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20220407-0009/
- lists.debian.org[debian-lts-announce] 20230524 [SECURITY] [DLA 3432-1] python2.7 security updatehttps://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- lists.debian.org[debian-lts-announce] 20230630 [SECURITY] [DLA 3477-1] python3.7 security updatehttps://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
- lists.debian.orghttps://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
- lists.debian.orghttps://lists.debian.org/debian-lts-announce/2024/11/msg00024.html
- cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html
07 Fixed in
AlmaLinux 8
- babel Fixed in 2.5.1-10.module_el8.6.0+2781+fed64c13
- platform-python Fixed in 3.6.8-45.el8.alma
- platform-python-debug Fixed in 3.6.8-45.el8.alma
- platform-python-devel Fixed in 3.6.8-45.el8.alma
- python-nose-docs Fixed
A version is affected if any line below covers it.
- Affected before 1.3.7-31.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.7-31.module_el8.6.0+2781+fed64c13
- python-psycopg2-doc Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
- python-sqlalchemy-doc Fixed
A version is affected if any line below covers it.
- Affected before 1.3.2-2.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.2-2.module_el8.6.0+2781+fed64c13
- python2 Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-Cython Fixed in 0.28.1-7.module_el8.6.0+2781+fed64c13
- python2-PyMySQL Fixed in 0.8.0-10.module_el8.6.0+2781+fed64c13
- python2-attrs Fixed in 17.4.0-10.module_el8.6.0+2781+fed64c13
- python2-babel Fixed in 2.5.1-10.module_el8.6.0+2781+fed64c13
- python2-backports Fixed in 1.0-16.module_el8.6.0+2781+fed64c13
- python2-backports-ssl_match_hostname Fixed in 3.5.0.1-12.module_el8.6.0+2781+fed64c13
- python2-bson Fixed in 3.7.0-1.module_el8.6.0+2781+fed64c13
- python2-chardet Fixed in 3.0.4-10.module_el8.6.0+2781+fed64c13
- python2-coverage Fixed in 4.5.1-4.module_el8.6.0+2781+fed64c13
- python2-debug Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-devel Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-dns Fixed in 1.15.0-10.module_el8.6.0+2781+fed64c13
- python2-docs Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
- python2-docs-info Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
- python2-docutils Fixed in 0.14-12.module_el8.6.0+2781+fed64c13
- python2-funcsigs Fixed in 1.0.2-13.module_el8.6.0+2781+fed64c13
- python2-idna Fixed in 2.5-7.module_el8.6.0+2781+fed64c13
- python2-ipaddress Fixed in 1.0.18-6.module_el8.6.0+2781+fed64c13
- python2-jinja2 Fixed in 2.10-9.module_el8.6.0+2781+fed64c13
- python2-libs Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-lxml Fixed in 4.2.3-6.module_el8.6.0+2781+fed64c13
- python2-markupsafe Fixed in 0.23-19.module_el8.6.0+2781+fed64c13
- python2-mock Fixed in 2.0.0-13.module_el8.6.0+2781+fed64c13
- python2-nose Fixed in 1.3.7-31.module_el8.6.0+2781+fed64c13
- python2-numpy Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-numpy-doc Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-numpy-f2py Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-pip Fixed in 9.0.3-19.module_el8.6.0+2781+fed64c13
- python2-pip-wheel Fixed in 9.0.3-19.module_el8.6.0+2781+fed64c13
- python2-pluggy Fixed in 0.6.0-8.module_el8.6.0+2781+fed64c13
- python2-psycopg2 Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
- python2-psycopg2-debug Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
116 further packages in AlmaLinux 8 not shown (first 40 listed).
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- babel Fixed in 2.5.1-10.module_el8.6.0+2781+fed64c13
- platform-python Fixed in 3.6.8-45.el8.alma
- platform-python-debug Fixed in 3.6.8-45.el8.alma
- platform-python-devel Fixed in 3.6.8-45.el8.alma
- python-nose-docs Fixed
A version is affected if any line below covers it.
- Affected before 1.3.7-31.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.7-31.module_el8.6.0+2781+fed64c13
- python-psycopg2-doc Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
- python-sqlalchemy-doc Fixed
A version is affected if any line below covers it.
- Affected before 1.3.2-2.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.2-2.module_el8.6.0+2781+fed64c13
- python2 Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-Cython Fixed in 0.28.1-7.module_el8.6.0+2781+fed64c13
- python2-PyMySQL Fixed in 0.8.0-10.module_el8.6.0+2781+fed64c13
- python2-attrs Fixed in 17.4.0-10.module_el8.6.0+2781+fed64c13
- python2-babel Fixed in 2.5.1-10.module_el8.6.0+2781+fed64c13
- python2-backports Fixed in 1.0-16.module_el8.6.0+2781+fed64c13
- python2-backports-ssl_match_hostname Fixed in 3.5.0.1-12.module_el8.6.0+2781+fed64c13
- python2-bson Fixed in 3.7.0-1.module_el8.6.0+2781+fed64c13
- python2-chardet Fixed in 3.0.4-10.module_el8.6.0+2781+fed64c13
- python2-coverage Fixed in 4.5.1-4.module_el8.6.0+2781+fed64c13
- python2-debug Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-devel Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-dns Fixed in 1.15.0-10.module_el8.6.0+2781+fed64c13
- python2-docs Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
- python2-docs-info Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
- python2-docutils Fixed in 0.14-12.module_el8.6.0+2781+fed64c13
- python2-funcsigs Fixed in 1.0.2-13.module_el8.6.0+2781+fed64c13
- python2-idna Fixed in 2.5-7.module_el8.6.0+2781+fed64c13
- python2-ipaddress Fixed in 1.0.18-6.module_el8.6.0+2781+fed64c13
- python2-jinja2 Fixed in 2.10-9.module_el8.6.0+2781+fed64c13
- python2-libs Fixed in 2.7.18-10.module_el8.6.0+2781+fed64c13.alma
- python2-lxml Fixed in 4.2.3-6.module_el8.6.0+2781+fed64c13
- python2-markupsafe Fixed in 0.23-19.module_el8.6.0+2781+fed64c13
- python2-mock Fixed in 2.0.0-13.module_el8.6.0+2781+fed64c13
- python2-nose Fixed in 1.3.7-31.module_el8.6.0+2781+fed64c13
- python2-numpy Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-numpy-doc Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-numpy-f2py Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
- python2-pip Fixed in 9.0.3-19.module_el8.6.0+2781+fed64c13
- python2-pip-wheel Fixed in 9.0.3-19.module_el8.6.0+2781+fed64c13
- python2-pluggy Fixed in 0.6.0-8.module_el8.6.0+2781+fed64c13
- python2-psycopg2 Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
- python2-psycopg2-debug Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
116 further packages in CloudLinux 8 not shown (first 40 listed).
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- pypy3 Fixed in 7.3.8+dfsg-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- pypy3 Fixed in 7.3.8+dfsg-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- pypy3 Fixed in 7.3.8+dfsg-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- python3.6 Fixed in 3.6.9-1~18.04ubuntu1.6
- python3.7 Fixed in 3.7.5-2ubuntu1~18.04.2
- python3.8 Fixed in 3.8.0-3ubuntu1~18.04.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- python3.8 Fixed in 3.8.10-0ubuntu1~20.04.2
- python3.9 Fixed in 3.9.5-3ubuntu0~20.04.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- python3.4 Fixed in 3.4.3-1ubuntu1~14.04.7+esm11Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.4~14.04.1+esm1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- python3.5 Fixed in 3.5.2-2ubuntu0~16.04.13+esm1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.