CVE-2021-45710: Tokio Race Condition Vulnerability

HIGH
Advisory Identifier: GHSA-fg7r-2g4j-5cgr
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CVSS 8.1
CWE-362
Published
Advisory Summary

CVE-2021-45710 is a HIGH (CVSS 8.1) race condition vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Tokio libraries in the crates.io ecosystem. The issue involves race condition in tokio. Remediation is available by upgrading affected packages to version 1.8.4, 1.13.1.

CVE-2021-45710 at a Glance

CVE Identifier CVE-2021-45710
GHSA Identifier GHSA-fg7r-2g4j-5cgr
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 Tokio
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-2021-45710

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

tokio fixed: 1.8.4 
Upgrade tokio to 1.8.4
tokio fixed: 1.13.1 
Upgrade tokio to 1.13.1
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 tokio

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-45710, inspect your project dependencies for Tokio:

inspect dependencies for tokio

Analyze the terminal output to locate any version of Tokio in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.8.4), 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-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 Tokio, 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

If a tokio::sync::oneshot channel is closed (via the oneshot::Receiver::close method), a data race may occur if the oneshot::Sender::send method is called while the corresponding oneshot::Receiver is awaited or calling try_recv. When these methods are called concurrently on a closed channel, the two halves of the channel can concurrently access a shared memory location, resulting in a data race. This has been observed to cause memory corruption. Note that the race only occurs when both halves of the channel are used after the Receiver half has called close. Code where close is not used, or where the Receiver is not awaited and try_recv is not called after calling close, is not affected.

CVE-2021-45710 Affected Tokio Versions

2 component(s)
Fixed Versions:
1.8.41.13.1
Product / Package Ecosystem Affected Versions Fixed Version
tokio
 crates.io
≥ 0.1.14
< 1.8.4
1.8.4
tokio
 crates.io
≥ 1.9.0
< 1.13.1
1.13.1

References

NVD — CVE-2021-45710 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-45710
Tokio Source Repository REPOSITORY
https://github.com/tokio-rs/tokio/issues/4225
Tokio Source Repository REPOSITORY
https://github.com/tokio-rs/tokio
raw.githubusercontent.com/rustsec/advisory-db... WEB
https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/tokio/RUSTSEC-2021-0124.md
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0124.html

Frequently Asked Questions

What is CVE-2021-45710?
CVE-2021-45710 is a security vulnerability in Tokio involving Race Condition in tokio under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Tokio versions are affected?
Affected versions include releases prior to 1.8.4, 1.13.1 across affected packages: tokio.
What version fixes CVE-2021-45710?
Upgrading to 1.8.4, 1.13.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tokio affected?
Yes, tokio is affected in releases prior to 1.8.4, 1.13.1. Upgrade your dependency to 1.8.4, 1.13.1 or later.
What is the CVSS score of CVE-2021-45710?
CVE-2021-45710 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-2021-45710?
CVE-2021-45710 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-2021-45710?
Run the dependency tree command: 'inspect dependencies for tokio'. 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-fg7r-2g4j-5cgr",
  "modified" : "2023-06-13T22:01:00Z",
  "published" : "2022-01-06T22:04:37Z",
  "aliases" : [ "CVE-2021-45710" ],
  "summary" : "Race Condition in tokio",
  "details" : "If a tokio::sync::oneshot channel is closed (via the oneshot::Receiver::close method), a data race may occur if the oneshot::Sender::send method is called while the corresponding oneshot::Receiver is awaited or calling try_recv.\n\nWhen these methods are called concurrently on a closed channel, the two halves of the channel can concurrently access a shared memory location, resulting in a data race. This has been observed to cause memory corruption.\n\nNote that the race only occurs when both halves of the channel are used after the Receiver half has called close. Code where close is not used, or where the Receiver is not awaited and try_recv is not called after calling close, is not affected.\n\n",
  "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" : "tokio"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.1.14"
      }, {
        "fixed" : "1.8.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "tokio"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.9.0"
      }, {
        "fixed" : "1.13.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-45710"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tokio-rs/tokio/issues/4225"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/tokio-rs/tokio"
  }, {
    "type" : "WEB",
    "url" : "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/tokio/RUSTSEC-2021-0124.md"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0124.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-01-05T22:43:36Z",
    "nvd_published_at" : "2021-12-27T00:15:00Z"
  }
}