CVE-2023-37365: Hnswlib Hnswlib Double Free Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-xwc8-rf6m-xr86
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CVSS 6.5
CWE-415
Published
Advisory Summary

CVE-2023-37365 is a MODERATE (CVSS 6.5) hnswlib double free vulnerability vulnerability (CWE-415: Double Free) affecting Hnswlib libraries in the PyPI ecosystem. The issue involves hnswlib double free vulnerability. Remediation is available by upgrading affected packages to version 0.8.0.

CVE-2023-37365 at a Glance

CVE Identifier CVE-2023-37365
GHSA Identifier GHSA-xwc8-rf6m-xr86
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-415: Double Free
Affected Product Hnswlib
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:R/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 Required (UI:R)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2023-37365

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

hnswlib fixed: 0.8.0 
pip install hnswlib>=0.8.0
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 hnswlib

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2023-37365, inspect your installed packages using pip:

pip show hnswlib

Analyze the terminal output to locate any version of Hnswlib in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.8.0), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-415: Double Free, where the product calls free() twice on the same memory address. In Hnswlib, 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

Hnswlib 0.7.0 has a double free in `init_index` when the M argument is a large integer.

CVE-2023-37365 Affected Hnswlib Versions

1 component(s)
Fixed Versions:
0.8.0
Product / Package Ecosystem Affected Versions Fixed Version
hnswlib
pypi/hnswlib
PyPI
< 0.8.0
0.8.0

References

NVD — CVE-2023-37365 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-37365
Hnswlib Source Repository REPOSITORY
https://github.com/nmslib/hnswlib/issues/467
Hnswlib Source Repository REPOSITORY
https://github.com/nmslib/hnswlib/pull/484
Security Fix Commit FIX COMMIT
https://github.com/nmslib/hnswlib/commit/f6d170ce0b41f9e75ace473b09df6e7872590757
Hnswlib Source Repository REPOSITORY
https://github.com/nmslib/hnswlib

Frequently Asked Questions

What is CVE-2023-37365?
CVE-2023-37365 is a security vulnerability in Hnswlib involving hnswlib Double Free vulnerability under CWE-415: Double Free.
Which Hnswlib versions are affected?
Affected versions include releases prior to 0.8.0 across affected packages: hnswlib.
What version fixes CVE-2023-37365?
Upgrading to 0.8.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hnswlib affected?
Yes, hnswlib is affected in releases prior to 0.8.0. Upgrade your dependency to 0.8.0 or later.
What is the CVSS score of CVE-2023-37365?
CVE-2023-37365 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2023-37365?
CVE-2023-37365 is classified under CWE-415: Double Free (The product calls free() twice on the same memory address.).
How can I check PyPI dependencies for CVE-2023-37365?
Run the dependency tree command: 'pip show hnswlib'. 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-xwc8-rf6m-xr86",
  "modified" : "2026-03-25T15:04:47Z",
  "published" : "2023-06-30T21:30:26Z",
  "aliases" : [ "CVE-2023-37365" ],
  "summary" : "hnswlib Double Free vulnerability",
  "details" : "Hnswlib 0.7.0 has a double free in `init_index` when the M argument is a large integer.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "hnswlib"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-37365"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nmslib/hnswlib/issues/467"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nmslib/hnswlib/pull/484"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nmslib/hnswlib/commit/f6d170ce0b41f9e75ace473b09df6e7872590757"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nmslib/hnswlib"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-415" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-06-30T22:12:53Z",
    "nvd_published_at" : "2023-06-30T19:15:09Z"
  }
}