CVE-2020-35904: Crossbeam channel Incorrect Buffer Size Vulnerability

MODERATE
Advisory Identifier: GHSA-m8h8-v6jh-c762
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CVSS 5.5
CWE-131
Published
Advisory Summary

CVE-2020-35904 is a MODERATE (CVSS 5.5) incorrect buffer size vulnerability (CWE-131: Incorrect Calculation of Buffer Size) affecting Crossbeam channel libraries in the crates.io ecosystem. The issue involves incorrect buffer size in crossbeam-channel. Remediation is available by upgrading affected packages to version 0.4.4.

CVE-2020-35904 at a Glance

CVE Identifier CVE-2020-35904
GHSA Identifier GHSA-m8h8-v6jh-c762
Severity MODERATE
CVSS v3.1 Base Score 5.5
CWE Classification CWE-131: Incorrect Calculation of Buffer Size
Affected Product Crossbeam channel
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 5.5

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

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2020-35904

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

crossbeam-channel fixed: 0.4.4 
Upgrade crossbeam-channel to 0.4.4
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 crossbeam-channel

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35904, inspect your project dependencies for Crossbeam channel:

inspect dependencies for crossbeam-channel

Analyze the terminal output to locate any version of Crossbeam channel in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.4.4), 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-131: Incorrect Calculation of Buffer Size, where the product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow. In Crossbeam channel, 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

The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.

CVE-2020-35904 Affected Crossbeam channel Versions

1 component(s)
Fixed Versions:
0.4.4
Product / Package Ecosystem Affected Versions Fixed Version
crossbeam-channel
 crates.io
≥ 0.4.3
< 0.4.4
0.4.4

References

NVD — CVE-2020-35904 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35904
Crossbeam channel Source Repository REPOSITORY
https://github.com/crossbeam-rs/crossbeam/pull/533
Crossbeam channel Source Repository REPOSITORY
https://github.com/crossbeam-rs/crossbeam
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0052.html

Frequently Asked Questions

What is CVE-2020-35904?
CVE-2020-35904 is a security vulnerability in Crossbeam channel involving Incorrect buffer size in crossbeam-channel under CWE-131: Incorrect Calculation of Buffer Size.
Which Crossbeam channel versions are affected?
Affected versions include releases prior to 0.4.4 across affected packages: crossbeam-channel.
What version fixes CVE-2020-35904?
Upgrading to 0.4.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is crossbeam-channel affected?
Yes, crossbeam-channel is affected in releases prior to 0.4.4. Upgrade your dependency to 0.4.4 or later.
What is the CVSS score of CVE-2020-35904?
CVE-2020-35904 has a CVSS v3.1 base score of 5.5 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-35904?
CVE-2020-35904 is classified under CWE-131: Incorrect Calculation of Buffer Size (The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.).
How can I check crates.io dependencies for CVE-2020-35904?
Run the dependency tree command: 'inspect dependencies for crossbeam-channel'. 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-m8h8-v6jh-c762",
  "modified" : "2023-06-13T17:11:53Z",
  "published" : "2021-08-25T20:49:43Z",
  "aliases" : [ "CVE-2020-35904" ],
  "summary" : "Incorrect buffer size in crossbeam-channel",
  "details" : "The affected version of this crate's the bounded channel incorrectly assumes that Vec::from_iter has allocated capacity that same as the number of iterator elements. Vec::from_iter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::from_iter has allocated different sizes with the number of iterator elements.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "crossbeam-channel"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.4.3"
      }, {
        "fixed" : "0.4.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35904"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/crossbeam-rs/crossbeam/pull/533"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/crossbeam-rs/crossbeam"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0052.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-131" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T20:51:01Z",
    "nvd_published_at" : null
  }
}