CVE-2020-35909: Multihash Unexpected Panic Vulnerability

HIGH
Advisory Identifier: GHSA-h7qh-3h6f-w79p
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CVSS 7.5
CWE-20
Published
Advisory Summary

CVE-2020-35909 is a HIGH (CVSS 7.5) unexpected panic vulnerability (CWE-20: Improper Input Validation) affecting Multihash libraries in the crates.io ecosystem. The issue involves unexpected panic in multihash. Remediation is available by upgrading affected packages to version 0.11.3.

CVE-2020-35909 at a Glance

CVE Identifier CVE-2020-35909
GHSA Identifier GHSA-h7qh-3h6f-w79p
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-20: Improper Input Validation
Affected Product Multihash
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 7.5

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
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-2020-35909

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

multihash fixed: 0.11.3 
Upgrade multihash to 0.11.3
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 multihash

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-35909, inspect your project dependencies for Multihash:

inspect dependencies for multihash

Analyze the terminal output to locate any version of Multihash in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.11.3), 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Multihash, 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

In versions prior 0.11.3 it's possible to make from_slice panic by feeding it certain malformed input. It's never documented that from_slice (and from_bytes which wraps it) can panic, and its' return type (Result<Self, DecodeError>) suggests otherwise. In practice, from_slice/from_bytes is frequently used in networking code and is being called with unsanitized data from untrusted sources. This can allow attackers to cause DoS by causing an unexpected panic in the network client's code..

CVE-2020-35909 Affected Multihash Versions

1 component(s)
Fixed Versions:
0.11.3
Product / Package Ecosystem Affected Versions Fixed Version
multihash
 crates.io
< 0.11.3
0.11.3

References

NVD — CVE-2020-35909 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-35909
Multihash Source Repository REPOSITORY
https://github.com/multiformats/rust-multihash/pull/72
Multihash Source Repository REPOSITORY
https://github.com/multiformats/rust-multihash
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2020-0068.html

Frequently Asked Questions

What is CVE-2020-35909?
CVE-2020-35909 is a security vulnerability in Multihash involving Unexpected panic in multihash under CWE-20: Improper Input Validation.
Which Multihash versions are affected?
Affected versions include releases prior to 0.11.3 across affected packages: multihash.
What version fixes CVE-2020-35909?
Upgrading to 0.11.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is multihash affected?
Yes, multihash is affected in releases prior to 0.11.3. Upgrade your dependency to 0.11.3 or later.
What is the CVSS score of CVE-2020-35909?
CVE-2020-35909 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-35909?
CVE-2020-35909 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check crates.io dependencies for CVE-2020-35909?
Run the dependency tree command: 'inspect dependencies for multihash'. 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-h7qh-3h6f-w79p",
  "modified" : "2023-06-13T20:05:17Z",
  "published" : "2021-08-25T20:49:41Z",
  "aliases" : [ "CVE-2020-35909" ],
  "summary" : "Unexpected panic in multihash",
  "details" : "In versions prior 0.11.3 it's possible to make from_slice panic by feeding it certain malformed input. It's never documented that from_slice (and from_bytes which wraps it) can panic, and its' return type (Result<Self, DecodeError>) suggests otherwise. In practice, from_slice/from_bytes is frequently used in networking code and is being called with unsanitized data from untrusted sources. This can allow attackers to cause DoS by causing an unexpected panic in the network client's code..",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "multihash"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.11.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-35909"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/multiformats/rust-multihash/pull/72"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/multiformats/rust-multihash"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2020-0068.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T20:51:29Z",
    "nvd_published_at" : null
  }
}