01 Record

CVE-2020-26116

http.client in Python 3.x before 3.5.10, 3.6.x before 3.6.12, 3.7.x before 3.7.9, and 3.8.x before 3.8.5 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by

UnratedPUBLISHEDCNA: mitre

CNA base scoreUnratedNo CNA CVSS vector

View raw JSON

02 Description

http.client in Python 3.x before 3.5.10, 3.6.x before 3.6.12, 3.7.x before 3.7.9, and 3.8.x before 3.8.5 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by

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.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

6.35% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 93.6% of scored records. A rank, not a probability.

NVD base score

7.2 (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:C/C:L/I:L/A:N

NVD analysis status

Modified. NVD last modified this record on 2026-10-14.

Red Hat severity

Moderate. 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

2020-09-27 00:00Z6 YR AGO

Last updated

2026-10-14 09:35Z15 DAYS AGO

Reserved

2020-09-27

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')Class
CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')Variant

Data version

5.2

Document digest

b1055d4de69769232e5adf3d354f022a91caaeb8258500b2a5eacc187f4bb64d

05 Affected products

VendorProductVersionsPlatforms

canonicalubuntu_linuxNot specified—

debiandebian_linuxNot specified—

fedoraprojectfedoraNot specified—

netapphci_compute_nodeNot specified—

netapphci_storage_nodeNot specified—

netappsolidfireNot specified—

opensuseleapNot specified—

oraclezfs_storage_appliance_kitNot specified—

pythonpythonNot specified—

redhatenterprise_linuxNot specified—

redhatquayNot specified—

redhatrhel_eusNot specified—

redhatrhel_software_collectionsNot specified—

06 References

python-security.readthedocs.iohttps://python-security.readthedocs.io/vuln/http-header-injection-method.html
bugs.python.orghttps://bugs.python.org/issue39603
lists.fedoraproject.orgFEDORA-2020-221823ebddhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BW4GCLQISJCOEGQNIMVUZDQMIY6RR6CC/vendor-advisory
lists.fedoraproject.orgFEDORA-2020-887d3fa26fhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JWMAVY4T4257AZHTF2RZJKNJNSJFY24O/vendor-advisory
lists.fedoraproject.orgFEDORA-2020-d30881c970https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OXI72HIHMXCQFWTULUXDG7VDA2BCYL4Y/vendor-advisory
usn.ubuntu.comUSN-4581-1https://usn.ubuntu.com/4581-1/vendor-advisory
lists.fedoraproject.orgFEDORA-2020-e33acdea18https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HDQ2THWU4GPV4Y5H5WW5PFMSWXL2CRFD/vendor-advisory
lists.opensuse.orgopenSUSE-SU-2020:1859http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00027.htmlvendor-advisory
lists.fedoraproject.orgFEDORA-2020-d42cb01973https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QOX7DGMMWWL6POCRYGAUCISOLR2IG3XV/vendor-advisory
lists.debian.org[debian-lts-announce] 20201119 [SECURITY] [DLA 2456-1] python3.5 security updatehttps://lists.debian.org/debian-lts-announce/2020/11/msg00032.htmlmailing-list
security.gentoo.orgGLSA-202101-18https://security.gentoo.org/glsa/202101-18vendor-advisory
www.oracle.comhttps://www.oracle.com/security-alerts/cpuoct2021.html
security.netapp.comhttps://security.netapp.com/advisory/ntap-20201023-0001/
lists.debian.org[debian-lts-announce] 20230524 [SECURITY] [DLA 3432-1] python2.7 security updatehttps://lists.debian.org/debian-lts-announce/2023/05/msg00024.htmlmailing-list
cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html

07 Fixed in

AlmaLinux 8

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-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-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-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-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-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-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-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
python2-psycopg2-tests
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-py
Fixed in 1.5.3-6.module_el8.6.0+2781+fed64c13
python2-pysocks
Fixed in 1.6.8-6.module_el8.6.0+2781+fed64c13
python2-pytest
Fixed in 3.4.2-13.module_el8.6.0+2781+fed64c13
python2-pytest-mock
Fixed in 1.9.0-4.module_el8.6.0+2781+fed64c13
python2-pytz
Fixed in 2017.2-12.module_el8.6.0+2781+fed64c13
python2-pyyaml
Fixed in 3.12-16.module_el8.6.0+2781+fed64c13
python2-requests
Fixed in 2.20.0-3.module_el8.6.0+2781+fed64c13
python2-rpm-macros
Fixed in 3-38.module_el8.6.0+2781+fed64c13
python2-setuptools
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools-wheel
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools_scm
Fixed in 1.15.7-6.module_el8.6.0+2781+fed64c13
python2-six
Fixed in 1.11.0-6.module_el8.6.0+2781+fed64c13
python2-sqlalchemy
Fixed in 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-urllib3
Fixed in 1.24.2-3.module_el8.6.0+2781+fed64c13
python38-Cython
Fixed in 0.29.14-4.module_el8.6.0+2778+cd494b30

18 further packages in AlmaLinux 8 not shown (first 40 listed).

CloudLinux 8

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-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-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-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-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-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-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-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
python2-psycopg2-tests
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-py
Fixed in 1.5.3-6.module_el8.6.0+2781+fed64c13
python2-pysocks
Fixed in 1.6.8-6.module_el8.6.0+2781+fed64c13
python2-pytest
Fixed in 3.4.2-13.module_el8.6.0+2781+fed64c13
python2-pytest-mock
Fixed in 1.9.0-4.module_el8.6.0+2781+fed64c13
python2-pytz
Fixed in 2017.2-12.module_el8.6.0+2781+fed64c13
python2-pyyaml
Fixed in 3.12-16.module_el8.6.0+2781+fed64c13
python2-requests
Fixed in 2.20.0-3.module_el8.6.0+2781+fed64c13
python2-rpm-macros
Fixed in 3-38.module_el8.6.0+2781+fed64c13
python2-setuptools
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools-wheel
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools_scm
Fixed in 1.15.7-6.module_el8.6.0+2781+fed64c13
python2-six
Fixed in 1.11.0-6.module_el8.6.0+2781+fed64c13
python2-sqlalchemy
Fixed in 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-urllib3
Fixed in 1.24.2-3.module_el8.6.0+2781+fed64c13
python38-Cython
Fixed in 0.29.14-4.module_el8.6.0+2778+cd494b30

18 further packages in CloudLinux 8 not shown (first 40 listed).

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Debian 12

pypy3
Fixed in 7.3.3+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

pypy3
Fixed in 7.3.3+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

pypy3
Fixed in 7.3.3+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

python3.5
Fixed in 3.5.2-2ubuntu0~16.04.12

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

python3.6
Fixed in 3.6.9-1~18.04ubuntu1.3

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+esm8
Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
python3.5
Fixed in 3.5.2-2ubuntu0~16.04.4~14.04.1+esm1
Available 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 18.04 LTS

python3.7
Fixed in 3.7.5-2ubuntu1~18.04.2+esm3
Available with Ubuntu Pro: https://ubuntu.com/pro
python3.8
Fixed in 3.8.0-3ubuntu1~18.04.2+esm2
Available with Ubuntu Pro: 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.