CVE-2025-3864: Hackney Hackney Fails To Properly Release Vulnerability

LOW
Advisory Identifier: GHSA-9fm9-hp7p-53mf
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CWE-772
Published
Advisory Summary

CVE-2025-3864 is a LOW hackney fails to properly release vulnerability (CWE-772: Missing Release of Resource after Effective Lifetime) affecting Hackney libraries in the Hex ecosystem. The issue involves hackney fails to properly release http connections to the pool. Remediation is available by upgrading affected packages to version 1.24.0.

CVE-2025-3864 at a Glance

CVE Identifier CVE-2025-3864
GHSA Identifier GHSA-9fm9-hp7p-53mf
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-772: Missing Release of Resource after Effective Lifetime
Affected Product Hackney
Package Ecosystem Hex
Published Date
Last Updated

How to Fix CVE-2025-3864

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

hackney fixed: 1.24.0 
Upgrade hackney to 1.24.0
Verify Direct and Transitive Dependencies

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

inspect dependencies for hackney

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-3864, inspect your project dependencies for Hackney:

inspect dependencies for hackney

Analyze the terminal output to locate any version of Hackney in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.24.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-772: Missing Release of Resource after Effective Lifetime, where the product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed. In Hackney, 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

Hackney fails to properly release HTTP connections to the pool after handling 307 Temporary Redirect responses. Remote attackers can exploit this to exhaust connection pools, causing denial of service in applications using the library. Fix for this issue has been included in 1.24.0 release.

CVE-2025-3864 Affected Hackney Versions

1 component(s)
Fixed Versions:
1.24.0
Product / Package Ecosystem Affected Versions Fixed Version
hackney
 Hex
< 1.24.0
1.24.0

References

NVD — CVE-2025-3864 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-3864
Hackney Source Repository REPOSITORY
https://github.com/benoitc/hackney/issues/717
Security Fix Commit FIX COMMIT
https://github.com/benoitc/hackney/commit/8f13ddac50d1626f8b9a47a08bd599e4efe1773d
cert.pl/en/posts/2025/05/cv... WEB
https://cert.pl/en/posts/2025/05/CVE-2025-3864
Hackney Source Repository REPOSITORY
https://github.com/benoitc/hackney

Frequently Asked Questions

What is CVE-2025-3864?
CVE-2025-3864 is a security vulnerability in Hackney involving Hackney fails to properly release HTTP connections to the pool under CWE-772: Missing Release of Resource after Effective Lifetime.
Which Hackney versions are affected?
Affected versions include releases prior to 1.24.0 across affected packages: hackney.
What version fixes CVE-2025-3864?
Upgrading to 1.24.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hackney affected?
Yes, hackney is affected in releases prior to 1.24.0. Upgrade your dependency to 1.24.0 or later.
What CWE is associated with CVE-2025-3864?
CVE-2025-3864 is classified under CWE-772: Missing Release of Resource after Effective Lifetime (The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.).
How can I check Hex dependencies for CVE-2025-3864?
Run the dependency tree command: 'inspect dependencies for hackney'. 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-9fm9-hp7p-53mf",
  "modified" : "2026-01-29T02:35:55Z",
  "published" : "2025-05-28T12:30:34Z",
  "aliases" : [ "CVE-2025-3864" ],
  "summary" : "Hackney fails to properly release HTTP connections to the pool",
  "details" : "Hackney fails to properly release HTTP connections to the pool after handling 307 Temporary Redirect responses. Remote attackers can exploit this to exhaust connection pools, causing denial of service in applications using the library.\nFix for this issue has been included in 1.24.0 release.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Hex",
      "name" : "hackney"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.24.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-3864"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/benoitc/hackney/issues/717"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/benoitc/hackney/commit/8f13ddac50d1626f8b9a47a08bd599e4efe1773d"
  }, {
    "type" : "WEB",
    "url" : "https://cert.pl/en/posts/2025/05/CVE-2025-3864"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/benoitc/hackney"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-772" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-05-28T16:08:47Z",
    "nvd_published_at" : "2025-05-28T12:15:19Z"
  }
}