CVE-2021-31996: Algorithmica Double Free Vulnerability

HIGH
Advisory Identifier: GHSA-jh37-772x-4hpw
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CVSS 7.5
CWE-415
Published
Advisory Summary

CVE-2021-31996 is a HIGH (CVSS 7.5) double free vulnerability (CWE-415: Double Free) affecting Algorithmica libraries in the crates.io ecosystem. The issue involves double free in algorithmica. Remediation is available in the latest vendor maintenance releases.

CVE-2021-31996 at a Glance

CVE Identifier CVE-2021-31996
GHSA Identifier GHSA-jh37-772x-4hpw
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-415: Double Free
Affected Product Algorithmica
Package Ecosystem crates.io
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-2021-31996

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

algorithmica fixed: Latest secure release 
Upgrade algorithmica to Latest secure release
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 algorithmica

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-31996, inspect your project dependencies for Algorithmica:

inspect dependencies for algorithmica

Analyze the terminal output to locate any version of Algorithmica 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: Verify declared build manifests and deployed runtime container environments.

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 Algorithmica, 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 the algorithmica crate through 2021-03-07 for Rust. In the affected versions of this crate, `merge_sort::merge()` wildly duplicates and drops ownership of `T` without guarding against double-free. Due to such implementation, simply invoking `merge_sort::merge()` on `Vec<T: Drop>` can cause **double free** bugs.

CVE-2021-31996 Affected Algorithmica Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
algorithmica
 crates.io
≤ 0.1.8

References

NVD — CVE-2021-31996 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-31996
Algorithmica Source Repository REPOSITORY
https://github.com/AbrarNitk/algorithmica/issues/1
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0053.html

Frequently Asked Questions

What is CVE-2021-31996?
CVE-2021-31996 is a security vulnerability in Algorithmica involving Double free in algorithmica under CWE-415: Double Free.
Which Algorithmica versions are affected?
Affected versions include releases prior to current release patches across affected packages: algorithmica.
What version fixes CVE-2021-31996?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is algorithmica affected?
Yes, algorithmica is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-31996?
CVE-2021-31996 has a CVSS v3.1 base score of 7.5 (HIGH) 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-2021-31996?
CVE-2021-31996 is classified under CWE-415: Double Free (The product calls free() twice on the same memory address.).
How can I check crates.io dependencies for CVE-2021-31996?
Run the dependency tree command: 'inspect dependencies for algorithmica'. 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-jh37-772x-4hpw",
  "modified" : "2021-08-24T19:12:12Z",
  "published" : "2021-08-25T21:01:52Z",
  "aliases" : [ "CVE-2021-31996" ],
  "summary" : "Double free in algorithmica",
  "details" : "An issue was discovered in the algorithmica crate through 2021-03-07 for Rust. In the affected versions of this crate, `merge_sort::merge()` wildly duplicates and drops ownership of `T` without guarding against double-free. Due to such implementation, simply invoking `merge_sort::merge()` on `Vec<T: Drop>` can cause **double free** bugs.\n",
  "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" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "algorithmica"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.1.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-31996"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/AbrarNitk/algorithmica/issues/1"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0053.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-415" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-25T20:52:19Z",
    "nvd_published_at" : null
  }
}