CVE-2021-3737

highpriority · track · 35EPSS 0.132 · 96 %ileDEEUFRRUUS
grimoire priorityP1 · Urgent
Exploitable?
—
no known exploitation
Likely / severe?
13.2% (96th) EPSS
CVSS 7.1 · high
Is it mine?
131 products
Check your exposure
Who says so?
9 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

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 loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–7.5

v2.07.1highAV:N/AC:M/Au:N/C:N/I:N/A:Cprimary · NVD / NIST USexploitability 8.6 · impact 6.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:Csecondary · CISA US
v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:Csecondary · Siemens ProductCERT DE
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:Hsecondary · Red Hat Product Security US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USprimaryCWE-835USprimaryCWE-400USCWE-400USCWE-400USCWE-835US
05

affected products (131)

Products and version ranges known to be affected.

showing 20 of 131
06

advisories (13)

Vendor and ecosystem advisories describing this.

  • RHSA-2022:1986Red Hat Security Advisory: python3 security update2022-05-10csaf · redhat_csafUS

    An update for python3 is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

  • SSA-398330SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.52023-12-12csaf · siemens_psirtDE

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 are no longer maintained and there won't be any update to the CVE list anymore. Please update to the latest version. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 (https://cert-portal.siemens.com/productcert/html/ssb-439005.html).

  • WID-SEC-W-2022-0011Python: Mehrere SchwachstellenDeutsch2022-05-10csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Python ausnutzen, um einen Denial of Service Angriff durchzuführen und um Informationen offenzulegen.

  • WID-SEC-W-2022-0302Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen Ausführen von beliebigem Programmcode mit AdministratorrechtenDeutsch2022-06-14csaf · cert_bundDE

    Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um beliebigen Programmcode auszuführen, einen Cross-Site-Scripting-Angriff durchzuführen, Informationen offenzulegen, einen Denial-of-Service-Zustand zu verursachen oder Dateien zu manipulieren.

  • WID-SEC-W-2022-0432Xerox FreeFlow Print Server: Mehrere SchwachstellenDeutsch2022-06-21csaf · cert_bundDE

    Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um die Vertraulichkeit, Verfügbarkeit und Integrität zu gefährden.

  • WID-SEC-W-2023-0141Oracle Database Server: Mehrere SchwachstellenDeutsch2023-01-17csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Oracle Database Server ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

  • WID-SEC-W-2023-1524IBM Spectrum Protect Plus: Mehrere SchwachstellenDeutsch2022-01-31csaf · cert_bundDE

    Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in IBM Spectrum Protect Plus ausnutzen, um einen Denial-of-Service-Zustand zu verursachen, seine Privilegien zu erweitern, Sicherheitsmaßnahmen zu umgehen und beliebigen Code auszuführen.

  • ICSA-23-348-10Siemens SIMATIC S7-15002023-12-12icsa · cisa_csaf_otUS

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 ( https://cert-portal.siemens.com/productcert/html/ssb-439005.html).

  • BIT-libpython-2021-37372025-08-11vendor · osvUS

    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 loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

  • BIT-python-2021-37372024-03-06vendor · osvUS

    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 loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

  • BIT-python-min-2021-37372025-01-16vendor · osvUS

    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 loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

  • CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
  • PSF-2022-7CVE-2021-3737: urllib HTTP client possible infinite loop on a 100 Continue response2022-03-04vendor · osvUS

    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 loop, consuming CPU time. The highest threat from this vulnerability is to system availability.

07

also known as (8)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bduosvcert_bundcisa_csaf_otredhat_csafsiemens_psirtcertfrNVDCVE.orgMITRE
published 2022-03-04modified 2026-06-17
10

references (81)

External citations — patches, advisories, analysis.

scry

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