CVE-2021-34337: Mailman Mailman Core Vulnerable To Timing Vulnerability

HIGH
Advisory Identifier: GHSA-2jg5-xgvv-4wq7
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CVSS 6.3
CWE-208
Published
Advisory Summary

CVE-2021-34337 is a HIGH (CVSS 6.3) mailman core vulnerable to timing vulnerability (CWE-208: Observable Timing Discrepancy) affecting Mailman libraries in the PyPI ecosystem. The issue involves mailman core vulnerable to timing attacks. Remediation is available by upgrading affected packages to version 3.3.5.

CVE-2021-34337 at a Glance

CVE Identifier CVE-2021-34337
GHSA Identifier GHSA-2jg5-xgvv-4wq7
Severity HIGH
CVSS v3.1 Base Score 6.3
CWE Classification CWE-208: Observable Timing Discrepancy
Affected Product Mailman
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.3

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

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

How to Fix CVE-2021-34337

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

mailman fixed: 3.3.5 
pip install mailman>=3.3.5
Verify Direct and Transitive Dependencies

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

pip show mailman

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2021-34337, inspect your installed packages using pip:

pip show mailman

Analyze the terminal output to locate any version of Mailman in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.3.5), your application is affected.

Note: The pip show mailman command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-208: Observable Timing Discrepancy, where two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not. In Mailman, 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

An issue was discovered in Mailman Core before 3.3.5. An attacker with access to the REST API could use timing attacks to determine the value of the configured REST API password and then make arbitrary REST API calls. The REST API is bound to localhost by default, limiting the ability for attackers to exploit this, but can optionally be made to listen on other interfaces.

CVE-2021-34337 Affected Mailman Versions

1 component(s)
Fixed Versions:
3.3.5
Product / Package Ecosystem Affected Versions Fixed Version
mailman
pypi/mailman
PyPI
< 3.3.5
3.3.5

References

NVD — CVE-2021-34337 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-34337
Mailman Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/mailman/PYSEC-2023-22.yaml
gitlab.com/mailman/mailman PACKAGE
https://gitlab.com/mailman/mailman
gitlab.com/mailman/mailman/-/c... WEB
https://gitlab.com/mailman/mailman/-/commit/e4a39488c4510fcad8851217f10e7337a196bb51
gitlab.com/mailman/mailman/-/i... WEB
https://gitlab.com/mailman/mailman/-/issues/911
gitlab.com/mailman/mailman/-/t... WEB
https://gitlab.com/mailman/mailman/-/tags

Frequently Asked Questions

What is CVE-2021-34337?
CVE-2021-34337 is a security vulnerability in Mailman involving Mailman Core vulnerable to timing attacks under CWE-208: Observable Timing Discrepancy.
Which Mailman versions are affected?
Affected versions include releases prior to 3.3.5 across affected packages: mailman.
What version fixes CVE-2021-34337?
Upgrading to 3.3.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mailman affected?
Yes, mailman is affected in releases prior to 3.3.5. Upgrade your dependency to 3.3.5 or later.
What is the CVSS score of CVE-2021-34337?
CVE-2021-34337 has a CVSS v3.1 base score of 6.3 (HIGH) with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2021-34337?
CVE-2021-34337 is classified under CWE-208: Observable Timing Discrepancy (Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.).
How can I check PyPI dependencies for CVE-2021-34337?
Run the dependency tree command: 'pip show mailman'. 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-2jg5-xgvv-4wq7",
  "modified" : "2024-09-30T16:52:42Z",
  "published" : "2023-04-15T21:30:16Z",
  "aliases" : [ "CVE-2021-34337" ],
  "summary" : "Mailman Core vulnerable to timing attacks",
  "details" : "An issue was discovered in Mailman Core before 3.3.5. An attacker with access to the REST API could use timing attacks to determine the value of the configured REST API password and then make arbitrary REST API calls. The REST API is bound to localhost by default, limiting the ability for attackers to exploit this, but can optionally be made to listen on other interfaces.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mailman"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.3.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-34337"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/mailman/PYSEC-2023-22.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://gitlab.com/mailman/mailman"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/mailman/mailman/-/commit/e4a39488c4510fcad8851217f10e7337a196bb51"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/mailman/mailman/-/issues/911"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/mailman/mailman/-/tags"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-208" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-04-18T13:05:08Z",
    "nvd_published_at" : "2023-04-15T20:16:00Z"
  }
}