CVE-2021-28032: Nano arena Use After Free Vulnerability

CRITICAL
Advisory Identifier: GHSA-wp34-mqw5-jj85
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CVSS 9.8
CWE-416
Published
Advisory Summary

CVE-2021-28032 is a CRITICAL (CVSS 9.8) use after free vulnerability (CWE-416: Use After Free) affecting Nano arena libraries in the crates.io ecosystem. The issue involves use after free in nano_arena. Remediation is available by upgrading affected packages to version 0.5.2.

CVE-2021-28032 at a Glance

CVE Identifier CVE-2021-28032
GHSA Identifier GHSA-wp34-mqw5-jj85
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-416: Use After Free
Affected Product Nano arena
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-2021-28032

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

nano_arena fixed: 0.5.2 
Upgrade nano_arena to 0.5.2
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 nano_arena

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-28032, inspect your project dependencies for Nano arena:

inspect dependencies for nano_arena

Analyze the terminal output to locate any version of Nano arena in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.5.2), 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 CWE-416: Use After Free, where the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. In Nano arena, 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 this crate assumed that Borrow<Idx> was guaranteed to return the same value on .borrow(). The borrowed index value was used to retrieve a mutable reference to a value. If the Borrow<Idx> implementation returned a different index, the split arena would allow retrieving the index as a mutable reference creating two mutable references to the same element. This violates Rust's aliasing rules and allows for memory safety issues such as writing out of bounds and use-after-frees. The flaw was corrected in commit `6b83f9d` by storing the .borrow() value in a temporary variable.

CVE-2021-28032 Affected Nano arena Versions

1 component(s)
Fixed Versions:
0.5.2
Product / Package Ecosystem Affected Versions Fixed Version
nano_arena
 crates.io
< 0.5.2
0.5.2

References

NVD — CVE-2021-28032 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-28032
Nano arena Source Repository REPOSITORY
https://github.com/bennetthardwick/nano-arena/issues/1
Security Fix Commit FIX COMMIT
https://github.com/bennetthardwick/nano-arena/commit/6b83f9d0708337a9f8b709c1624a8587021ceba2
Nano arena Source Repository REPOSITORY
https://github.com/bennetthardwick/nano-arena
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0031.html

Frequently Asked Questions

What is CVE-2021-28032?
CVE-2021-28032 is a security vulnerability in Nano arena involving Use after free in nano_arena under CWE-416: Use After Free.
Which Nano arena versions are affected?
Affected versions include releases prior to 0.5.2 across affected packages: nano_arena.
What version fixes CVE-2021-28032?
Upgrading to 0.5.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is nano_arena affected?
Yes, nano_arena is affected in releases prior to 0.5.2. Upgrade your dependency to 0.5.2 or later.
What is the CVSS score of CVE-2021-28032?
CVE-2021-28032 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-2021-28032?
CVE-2021-28032 is classified under CWE-416: Use After Free (The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.).
How can I check crates.io dependencies for CVE-2021-28032?
Run the dependency tree command: 'inspect dependencies for nano_arena'. 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-wp34-mqw5-jj85",
  "modified" : "2023-06-13T20:02:46Z",
  "published" : "2021-08-25T20:52:00Z",
  "aliases" : [ "CVE-2021-28032" ],
  "summary" : "Use after free in nano_arena",
  "details" : "Affected versions of this crate assumed that Borrow<Idx> was guaranteed to return the same value on .borrow(). The borrowed index value was used to retrieve a mutable reference to a value.\n\nIf the Borrow<Idx> implementation returned a different index, the split arena would allow retrieving the index as a mutable reference creating two mutable references to the same element. This violates Rust's aliasing rules and allows for memory safety issues such as writing out of bounds and use-after-frees.\n\nThe flaw was corrected in commit `6b83f9d` by storing the .borrow() value in a temporary variable.",
  "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" : "nano_arena"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-28032"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bennetthardwick/nano-arena/issues/1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bennetthardwick/nano-arena/commit/6b83f9d0708337a9f8b709c1624a8587021ceba2"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/bennetthardwick/nano-arena"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0031.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-416" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T17:23:52Z",
    "nvd_published_at" : null
  }
}