CVE-2021-45709: Crypto2 Use Of A Broken Or Vulnerability

CRITICAL
Advisory Identifier: GHSA-9hfg-pxr6-q4vp
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CVSS 9.8
CWE-119
Published
Advisory Summary

CVE-2021-45709 is a CRITICAL (CVSS 9.8) use of a broken or vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) affecting Crypto2 libraries in the crates.io ecosystem. The issue involves use of a broken or risky cryptographic algorithm in crypto2. Remediation is available in the latest vendor maintenance releases.

CVE-2021-45709 at a Glance

CVE Identifier CVE-2021-45709
GHSA Identifier GHSA-9hfg-pxr6-q4vp
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
Affected Product Crypto2
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/I:H/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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-45709

To remediate this vulnerability, upgrade all affected Crypto2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

crypto2 fixed: Latest secure release 
Upgrade crypto2 to Latest secure release
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 crypto2

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-45709, inspect your project dependencies for Crypto2:

inspect dependencies for crypto2

Analyze the terminal output to locate any version of Crypto2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), 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-119: Improper Restriction of Operations within the Bounds of a Memory Buffer, where the product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. this may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data. In Crypto2, 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 implementation does not enforce alignment requirements on input slices while incorrectly assuming 4-byte alignment through an unsafe call to std::slice::from_raw_parts_mut, which breaks the contract and introduces undefined behavior. This affects Chacha20 encryption and decryption in crypto2.

CVE-2021-45709 Affected Crypto2 Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
crypto2
 crates.io
≤ 0.1.2

References

NVD — CVE-2021-45709 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-45709
Crypto2 Source Repository REPOSITORY
https://github.com/shadowsocks/crypto2/issues/27
Crypto2 Source Repository REPOSITORY
https://github.com/shadowsocks/crypto2
raw.githubusercontent.com/rustsec/advisory-db... WEB
https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/crypto2/RUSTSEC-2021-0121.md
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0121.html

Frequently Asked Questions

What is CVE-2021-45709?
CVE-2021-45709 is a security vulnerability in Crypto2 involving Use of a Broken or Risky Cryptographic Algorithm in crypto2 under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer.
Which Crypto2 versions are affected?
Affected versions include releases prior to current release patches across affected packages: crypto2.
What version fixes CVE-2021-45709?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is crypto2 affected?
Yes, crypto2 is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-45709?
CVE-2021-45709 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-45709?
CVE-2021-45709 is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer (The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.).
How can I check crates.io dependencies for CVE-2021-45709?
Run the dependency tree command: 'inspect dependencies for crypto2'. 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-9hfg-pxr6-q4vp",
  "modified" : "2023-06-13T17:23:04Z",
  "published" : "2022-01-06T22:04:51Z",
  "aliases" : [ "CVE-2021-45709" ],
  "summary" : "Use of a Broken or Risky Cryptographic Algorithm in crypto2",
  "details" : "The implementation does not enforce alignment requirements on input slices while incorrectly assuming 4-byte alignment through an unsafe call to std::slice::from_raw_parts_mut, which breaks the contract and introduces undefined behavior.\n\nThis affects Chacha20 encryption and decryption in crypto2.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "crypto2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.1.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-45709"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/shadowsocks/crypto2/issues/27"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/shadowsocks/crypto2"
  }, {
    "type" : "WEB",
    "url" : "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/crypto2/RUSTSEC-2021-0121.md"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0121.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-119" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-01-05T22:55:41Z",
    "nvd_published_at" : "2021-12-27T00:15:00Z"
  }
}