CVE-2020-36450: Bunch Data Races Vulnerability

HIGH
Advisory Identifier: GHSA-jwph-qp5h-f9wj
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CVSS 8.1
CWE-362 CWE-77
Published
Advisory Summary

CVE-2020-36450 is a HIGH (CVSS 8.1) data races vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Bunch libraries in the crates.io ecosystem. The issue involves data races in bunch. Remediation is available in the latest vendor maintenance releases.

CVE-2020-36450 at a Glance

CVE Identifier CVE-2020-36450
GHSA Identifier GHSA-jwph-qp5h-f9wj
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Product Bunch
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 8.1

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

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
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-2020-36450

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

bunch fixed: Latest secure release 
Upgrade bunch 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 bunch

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-36450, inspect your project dependencies for Bunch:

inspect dependencies for bunch

Analyze the terminal output to locate any version of Bunch 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-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'), where the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. In Bunch, 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 bunch crate through 2020-11-12 for Rust. Affected versions of this crate unconditionally implements `Send`/`Sync` for `Bunch<T>`. This allows users to insert `T: !Sync` to `Bunch<T>`. It is possible to create a data race to a `T: !Sync` by invoking the `Bunch::get()` API (which returns `&T`) from multiple threads. It is also possible to send `T: !Send` to other threads by inserting `T` inside `Bunch<T>` and sending `Bunch<T>` to another thread, allowing to create a data race by inserting types like `T = Rc<_>`. Such data races can lead to memory corruption.

CVE-2020-36450 Affected Bunch Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
bunch
 crates.io
≤ 0.1.0

References

NVD — CVE-2020-36450 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-36450
Bunch Source Repository REPOSITORY
https://github.com/krl/bunch/issues/1
Bunch Source Repository REPOSITORY
https://github.com/krl/bunch
raw.githubusercontent.com/rustsec/advisory-db... WEB
https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/bunch/RUSTSEC-2020-0130.md
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0130.html

Frequently Asked Questions

What is CVE-2020-36450?
CVE-2020-36450 is a security vulnerability in Bunch involving Data races in bunch under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Bunch versions are affected?
Affected versions include releases prior to current release patches across affected packages: bunch.
What version fixes CVE-2020-36450?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is bunch affected?
Yes, bunch 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-2020-36450?
CVE-2020-36450 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-36450?
CVE-2020-36450 is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') (The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.).
How can I check crates.io dependencies for CVE-2020-36450?
Run the dependency tree command: 'inspect dependencies for bunch'. 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-jwph-qp5h-f9wj",
  "modified" : "2021-08-24T18:33:33Z",
  "published" : "2021-08-25T20:59:18Z",
  "aliases" : [ "CVE-2020-36450" ],
  "summary" : "Data races in bunch",
  "details" : "An issue was discovered in the bunch crate through 2020-11-12 for Rust. \nAffected versions of this crate unconditionally implements `Send`/`Sync` for `Bunch<T>`.\nThis allows users to insert `T: !Sync` to `Bunch<T>`. It is possible to create a data race to a `T: !Sync` by invoking the `Bunch::get()` API (which returns `&T`) from multiple threads. It is also possible to send `T: !Send` to other threads by inserting `T` inside `Bunch<T>` and sending `Bunch<T>` to another thread, allowing to create a data race by inserting types like `T = Rc<_>`.\n\nSuch data races can lead to memory corruption.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "bunch"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.1.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-36450"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/krl/bunch/issues/1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/krl/bunch"
  }, {
    "type" : "WEB",
    "url" : "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/bunch/RUSTSEC-2020-0130.md"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0130.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362", "CWE-77" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-09T21:34:27Z",
    "nvd_published_at" : "2021-08-08T06:15:00Z"
  }
}