CVE-2021-3737: Software Security Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-hr7v-m862-8hh8
Share
CVSS 7.5
CWE-400 CWE-835
Published
Advisory Summary

CVE-2021-3737 is a LOW (CVSS 7.5) security vulnerability vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not properly control the allocation and maintenance of a limited resource.. Remediation is available in the latest vendor maintenance releases.

CVE-2021-3737 at a Glance

CVE Identifier CVE-2021-3737
GHSA Identifier GHSA-hr7v-m862-8hh8
Severity LOW
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-3737

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-3737, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

References

NVD — CVE-2021-3737 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3737
Software Source Repository REPOSITORY
https://github.com/python/cpython/pull/25916
Software Source Repository REPOSITORY
https://github.com/python/cpython/pull/26503
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/ea9327036680acc92d9f89eaf6f6a54d2f8d78d9
bugs.python.org/issue44022 WEB
https://bugs.python.org/issue44022
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=1995162
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
Software Source Repository REPOSITORY
https://github.com/python/cpython
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2024/11/msg00024.html
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html
Software Security Information SECURITY
https://python-security.readthedocs.io/vuln/urllib-100-continue-loop.html
Software Security Information SECURITY
https://security.netapp.com/advisory/ntap-20220407-0009
Software Security Information SECURITY
https://ubuntu.com/security/CVE-2021-3737
Software Security Information SECURITY
https://www.oracle.com/security-alerts/cpujul2022.html

Frequently Asked Questions

What is CVE-2021-3737?
CVE-2021-3737 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-400: Uncontrolled Resource Consumption.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2021-3737?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2021-3737?
CVE-2021-3737 has a CVSS v3.1 base score of 7.5 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-3737?
CVE-2021-3737 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Maven dependencies for CVE-2021-3737?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hr7v-m862-8hh8",
  "modified" : "2026-10-14T12:31:23Z",
  "published" : "2022-05-24T22:01:50Z",
  "aliases" : [ "CVE-2021-3737" ],
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3737"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/python/cpython/pull/25916"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/python/cpython/pull/26503"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/python/cpython/commit/ea9327036680acc92d9f89eaf6f6a54d2f8d78d9"
  }, {
    "type" : "WEB",
    "url" : "https://bugs.python.org/issue44022"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1995162"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-398330.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/python/cpython"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2024/11/msg00024.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2024/12/msg00000.html"
  }, {
    "type" : "WEB",
    "url" : "https://python-security.readthedocs.io/vuln/urllib-100-continue-loop.html"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20220407-0009"
  }, {
    "type" : "WEB",
    "url" : "https://ubuntu.com/security/CVE-2021-3737"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpujul2022.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-835" ],
    "severity" : "LOW",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2022-03-04T19:15:00Z"
  }
}