CVE-2020-35862: Bitvec Use After Free And Double Vulnerability

CRITICAL
Advisory Identifier: GHSA-7cjc-hvxf-gqh7
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CVSS 9.8
CWE-415 CWE-416
Published
Advisory Summary

CVE-2020-35862 is a CRITICAL (CVSS 9.8) use after free and double vulnerability (CWE-415: Double Free) affecting Bitvec libraries in the crates.io ecosystem. The issue involves use after free and double free in bitvec. Remediation is available by upgrading affected packages to version 0.17.4.

CVE-2020-35862 at a Glance

CVE Identifier CVE-2020-35862
GHSA Identifier GHSA-7cjc-hvxf-gqh7
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-415: Double Free
Affected Product Bitvec
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/I:H/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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-35862

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

bitvec fixed: 0.17.4 
Upgrade bitvec to 0.17.4
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 bitvec

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35862, inspect your project dependencies for Bitvec:

inspect dependencies for bitvec

Analyze the terminal output to locate any version of Bitvec in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.17.4), 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 Bitvec, 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 bitvec crate before 0.17.4 for Rust. BitVec to BitBox conversion leads to a use-after-free or double free.

CVE-2020-35862 Affected Bitvec Versions

1 component(s)
Fixed Versions:
0.17.4
Product / Package Ecosystem Affected Versions Fixed Version
bitvec
 crates.io
≥ 0.11.0
< 0.17.4
0.17.4

References

NVD — CVE-2020-35862 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35862
Bitvec Source Repository REPOSITORY
https://github.com/myrrlyn/bitvec/issues/55
Bitvec Source Repository REPOSITORY
https://github.com/myrrlyn/bitvec
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0007.html

Frequently Asked Questions

What is CVE-2020-35862?
CVE-2020-35862 is a security vulnerability in Bitvec involving Use after free and double free in bitvec under CWE-415: Double Free.
Which Bitvec versions are affected?
Affected versions include releases prior to 0.17.4 across affected packages: bitvec.
What version fixes CVE-2020-35862?
Upgrading to 0.17.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bitvec affected?
Yes, bitvec is affected in releases prior to 0.17.4. Upgrade your dependency to 0.17.4 or later.
What is the CVSS score of CVE-2020-35862?
CVE-2020-35862 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-35862?
CVE-2020-35862 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-2020-35862?
Run the dependency tree command: 'inspect dependencies for bitvec'. 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-7cjc-hvxf-gqh7",
  "modified" : "2021-08-19T21:18:16Z",
  "published" : "2021-08-25T20:47:39Z",
  "aliases" : [ "CVE-2020-35862" ],
  "summary" : "Use after free and double free in bitvec",
  "details" : "An issue was discovered in the bitvec crate before 0.17.4 for Rust. BitVec to BitBox conversion leads to a use-after-free or double free.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "bitvec"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.11.0"
      }, {
        "fixed" : "0.17.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35862"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/myrrlyn/bitvec/issues/55"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/myrrlyn/bitvec"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0007.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-415", "CWE-416" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T21:18:16Z",
    "nvd_published_at" : null
  }
}