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No exploitation reportedFix available

CVE-2020-26116

No exploitation reported by the sources we read.

  • Published2020-09-27
  • Fixed in3.8.5 · 3.7.9 · 3.6.12 · 3.5.10
  • WeaknessCWE-74

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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 inserting CR and LF control characters in the first argument of HTTPConnection.request.

Timeline

dates in UTC
  1. 2020-09-2704:15CVE publishedNVD

Versions per branch

NVD · OSV
Python
BranchAffectedFixed in
3.8≥ 3.8.0, < 3.8.53.8.5
3.7≥ 3.7.0, < 3.7.93.7.9
3.6≥ 3.6.0, < 3.6.123.6.12
3.x≥ 3.0.0, < 3.5.103.5.10
Canonical ubuntu linux
BranchAffectedFixed in
12.4= 12.04no fix published
14.4= 14.04no fix published
16.4= 16.04no fix published
18.4= 18.04no fix published
Fedoraproject fedora
BranchAffectedFixed in
31.x= 31no fix published
32.x= 32no fix published
33.x= 33no fix published

5 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • babelRocky Linux:8all versions · fixed in 0:2.5.1-9.module+el8.4.0+403+9ae17a31
  • babelRocky Linux:8all versions · fixed in 0:2.7.0-10.module+el8.4.0+570+c2eaf144
  • babelRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:2.5.1-9.module+el8.1.0+3111+de3f2d8eand 1 other package
  • babelRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:2.7.0-10.module+el8.4.0+8888+89bc7e79and 1 other package
  • CythonRocky Linux:8all versions · fixed in 0:0.28.1-7.module+el8.4.0+403+9ae17a31
  • CythonRocky Linux:8all versions · fixed in 0:0.28.1-7.module+el8.5.0+706+735ec4b3
  • CythonRocky Linux:8all versions · fixed in 0:0.29.14-4.module+el8.4.0+570+c2eaf144
  • CythonRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:0.28.1-7.module+el8.1.0+3111+de3f2d8eand 3 other packages

311 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-26116 Red Hat Product Security1,037 products fixed · 17 known affected

    python: CRLF injection via HTTP request method in httplib/http.client

    python.src as a component of Red Hat Enterprise Linux 5 · python as a component of Red Hat Enterprise Linux 6 · python-devel as a component of Red Hat Enterprise Linux 6 · +14 more

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more

  • RHSA-2022:5235 Red Hat Product Security72 products fixed

    Red Hat Security Advisory: python security update

  • RHSA-2021:3366 Red Hat Product Security56 products fixed

    Red Hat Security Advisory: python3 security update

  • RHSA-2021:1633 Red Hat Product Security56 products fixed

    Red Hat Security Advisory: python3 security update

5 more advisories

Full record on NVD

Fix

  1. Update Python to 3.8.5 · 3.7.9 · 3.6.12 · 3.5.10
  2. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  3. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  4. Vendor fix Red Hat Product Security RHSA-2022:5235 · 72 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  5. Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.
  6. No fix planned, says the vendor Red Hat Product Security CVE-2020-26116 · 8 productsOut of support scope
  7. No fix planned, says the vendor Red Hat Product Security CVE-2020-26116 · 8 productsWill not fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Published
2020-09-27
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-w7gf-rpqw-gx4f

Frequently asked questions

What is 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 inserting CR and LF control characters in the first argument of HTTPConnection.request.

Is CVE-2020-26116 actively exploited?

Active exploitation of CVE-2020-26116 has not been confirmed. Its EPSS score was 6.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-26116?

CVE-2020-26116 has a CVSS v3 base score of 7.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

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