ZeroDay Findings
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2021-3737

A flaw was found in python.

Published Mar 4, 2022 · catalog updated Oct 14, 2026 · A flaw was found

Check this week

CVE-2021-3737 is not in CISA KEV. FIRST estimates a 13.17% chance of exploitation in the next 30 days. Check whether you run A flaw was found.

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
13.17%
Remediation
Advisory link
Affected products
cpe canonical/ubuntu linux · cpe fedoraproject/fedora · cpe netapp/hci · cpe oracle/communications cloud native core binding support function · cpe python/python · cpe redhat/codeready linux builder

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe canonical/ubuntu linux14.04
  • cpe fedoraproject/fedora33
  • cpe netapp/hciversion unspecified
  • cpe oracle/communications cloud native core binding support function22.1.3
  • cpe python/pythonversion unspecified
  • cpe redhat/codeready linux builder8.0
  • cpe redhat/codeready linux builder for ibm z systems8.0
  • cpe redhat/codeready linux builder for power little endian8.0
  • cpe redhat/enterprise linux6.0

How to fix CVE-2021-3737

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-3737 is not in CISA KEV. FIRST estimates a 13.17% chance of exploitation in the next 30 days. Check whether you run A flaw was found.

Which versions are affected?

Compare what you have installed with canonical/ubuntu linux 14.04; oracle/communications cloud native core binding support function 22.1.3; redhat/codeready linux builder 8.0; redhat/codeready linux builder for ibm z systems 8.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption; CWE-835: Infinite Loop. EPSS 13.17%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 4, 2022 · NIST NVD

    Detected

    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.

  2. Oct 14, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2021-3737

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-3737

    30-day exploitation probability 13.2%

    first.org
  • NIST NVDVulnerability recordCVE-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 loop, consuming CPU time. The highest threat from this vulnerability is to syst

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.