CVE-2020-35908: Futures util Improper `Sync` Implementation On `FuturesUnordered` Vulnerability

MODERATE
Advisory Identifier: GHSA-5r9g-j7jj-hw6c
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CVSS 5.5
Published
Advisory Summary

CVE-2020-35908 is a MODERATE (CVSS 5.5) improper `sync` implementation on `futuresunordered` vulnerability (General Security Weakness) affecting Futures util libraries in the crates.io ecosystem. The issue involves improper `sync` implementation on `futuresunordered` in futures-utils can cause data corruption. Remediation is available by upgrading affected packages to version 0.3.2.

CVE-2020-35908 at a Glance

CVE Identifier CVE-2020-35908
GHSA Identifier GHSA-5r9g-j7jj-hw6c
Severity MODERATE
CVSS v3.1 Base Score 5.5
CWE Classification General Security Weakness
Affected Product Futures util
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-2020-35908

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

futures-util fixed: 0.3.2 
Upgrade futures-util to 0.3.2
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 futures-util

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35908, inspect your project dependencies for Futures util:

inspect dependencies for futures-util

Analyze the terminal output to locate any version of Futures util in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.3.2), 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 General Security Weakness. In Futures util, 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 futures-util crate before 0.3.2 for Rust. FuturesUnordered can lead to data corruption because Sync is mishandled.

CVE-2020-35908 Affected Futures util Versions

1 component(s)
Fixed Versions:
0.3.2
Product / Package Ecosystem Affected Versions Fixed Version
futures-util
 crates.io
≥ 0.3.0
< 0.3.2
0.3.2

References

NVD — CVE-2020-35908 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35908
Futures util Source Repository REPOSITORY
https://github.com/rust-lang/futures-rs/issues/2050
Futures util Source Repository REPOSITORY
https://github.com/rust-lang/futures-rs
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0062.html

Frequently Asked Questions

What is CVE-2020-35908?
CVE-2020-35908 is a security vulnerability in Futures util involving Improper `Sync` implementation on `FuturesUnordered` in futures-utils can cause data corruption under General Security Weakness.
Which Futures util versions are affected?
Affected versions include releases prior to 0.3.2 across affected packages: futures-util.
What version fixes CVE-2020-35908?
Upgrading to 0.3.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is futures-util affected?
Yes, futures-util is affected in releases prior to 0.3.2. Upgrade your dependency to 0.3.2 or later.
What is the CVSS score of CVE-2020-35908?
CVE-2020-35908 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-2020-35908?
CVE-2020-35908 is classified under General Security Weakness.
How can I check crates.io dependencies for CVE-2020-35908?
Run the dependency tree command: 'inspect dependencies for futures-util'. 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-5r9g-j7jj-hw6c",
  "modified" : "2022-06-16T23:55:31Z",
  "published" : "2022-05-24T17:37:49Z",
  "aliases" : [ "CVE-2020-35908" ],
  "summary" : "Improper `Sync` implementation on `FuturesUnordered` in futures-utils can cause data corruption",
  "details" : "An issue was discovered in the futures-util crate before 0.3.2 for Rust. FuturesUnordered can lead to data corruption because Sync is mishandled.",
  "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" : "futures-util"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.3.0"
      }, {
        "fixed" : "0.3.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35908"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-lang/futures-rs/issues/2050"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rust-lang/futures-rs"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0062.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-16T23:55:31Z",
    "nvd_published_at" : "2020-12-31T09:15:00Z"
  }
}