CVE-2020-35907: futures_task :noop_waker_ref Can Segfault Due To Vulnerability

MODERATE
Advisory Identifier: GHSA-p9m5-3hj7-cp5r
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CVSS 5.5
CWE-476
Published
Advisory Summary

CVE-2020-35907 is a MODERATE (CVSS 5.5) :noop_waker_ref can segfault due to vulnerability (CWE-476: NULL Pointer Dereference) affecting futures_task libraries in the crates.io ecosystem. The issue involves :noop_waker_ref can segfault due to dereferencing a null pointer. Remediation is available by upgrading affected packages to version 0.3.5.

CVE-2020-35907 at a Glance

CVE Identifier CVE-2020-35907
GHSA Identifier GHSA-p9m5-3hj7-cp5r
Severity MODERATE
CVSS v3.1 Base Score 5.5
CWE Classification CWE-476: NULL Pointer Dereference
Affected Product futures_task
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-2020-35907

To remediate this vulnerability, upgrade all affected futures_task 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-task fixed: 0.3.5 
Upgrade futures-task to 0.3.5
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-task

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35907, inspect your project dependencies for futures_task:

inspect dependencies for futures-task

Analyze the terminal output to locate any version of futures_task in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.3.5), 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-476: NULL Pointer Dereference, where the product dereferences a pointer that it expects to be valid but is null. In futures_task, 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

Affected versions of the crate used a UnsafeCell in thread-local storage to return a noop waker reference, assuming that the reference would never be returned from another thread. This resulted in a segmentation fault crash if Waker::wake_by_ref() was called on a waker returned from another thread due to it attempting to dereference a pointer that wasn't accessible from the main thread.

CVE-2020-35907 Affected futures_task Versions

1 component(s)
Fixed Versions:
0.3.5
Product / Package Ecosystem Affected Versions Fixed Version
futures-task
 crates.io
< 0.3.5
0.3.5

References

NVD — CVE-2020-35907 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35907
futures_task Source Repository REPOSITORY
https://github.com/rust-lang/futures-rs/issues/2091
futures_task Source Repository REPOSITORY
https://github.com/rust-lang/futures-rs
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0061.html

Frequently Asked Questions

What is CVE-2020-35907?
CVE-2020-35907 is a security vulnerability in futures_task involving :noop_waker_ref can segfault due to dereferencing a NULL pointer under CWE-476: NULL Pointer Dereference.
Which futures_task versions are affected?
Affected versions include releases prior to 0.3.5 across affected packages: futures-task.
What version fixes CVE-2020-35907?
Upgrading to 0.3.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is futures-task affected?
Yes, futures-task is affected in releases prior to 0.3.5. Upgrade your dependency to 0.3.5 or later.
What is the CVSS score of CVE-2020-35907?
CVE-2020-35907 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-2020-35907?
CVE-2020-35907 is classified under CWE-476: NULL Pointer Dereference (The product dereferences a pointer that it expects to be valid but is NULL.).
How can I check crates.io dependencies for CVE-2020-35907?
Run the dependency tree command: 'inspect dependencies for futures-task'. 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-p9m5-3hj7-cp5r",
  "modified" : "2023-06-13T17:24:56Z",
  "published" : "2022-05-24T17:37:49Z",
  "aliases" : [ "CVE-2020-35907" ],
  "summary" : "futures_task::noop_waker_ref can segfault due to dereferencing a NULL pointer",
  "details" : "Affected versions of the crate used a UnsafeCell in thread-local storage to return a noop waker reference, assuming that the reference would never be returned from another thread.\n\nThis resulted in a segmentation fault crash if Waker::wake_by_ref() was called on a waker returned from another thread due to it attempting to dereference a pointer that wasn't accessible from the main thread.",
  "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-task"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.3.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35907"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-lang/futures-rs/issues/2091"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rust-lang/futures-rs"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0061.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-476" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-06-16T23:58:57Z",
    "nvd_published_at" : "2020-12-31T09:15:00Z"
  }
}