CVE-2021-29939: Stackvector Out Of Bounds Write Vulnerability

HIGH
Advisory Identifier: GHSA-9frf-r7c7-j2vg
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CVSS 7.3
CWE-787
Published
Advisory Summary

CVE-2021-29939 is a HIGH (CVSS 7.3) out of bounds write vulnerability (CWE-787: Out-of-bounds Write) affecting Stackvector libraries in the crates.io ecosystem. The issue involves out of bounds write in stackvector. Remediation is available by upgrading affected packages to version 1.0.9.

CVE-2021-29939 at a Glance

CVE Identifier CVE-2021-29939
GHSA Identifier GHSA-9frf-r7c7-j2vg
Severity HIGH
CVSS v3.1 Base Score 7.3
CWE Classification CWE-787: Out-of-bounds Write
Affected Product Stackvector
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 7.3

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:L/I:L/A:L).

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 Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2021-29939

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

stackvector fixed: 1.0.9 
Upgrade stackvector to 1.0.9
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 stackvector

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-29939, inspect your project dependencies for Stackvector:

inspect dependencies for stackvector

Analyze the terminal output to locate any version of Stackvector in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.0.9), 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-787: Out-of-bounds Write, where the product writes data past the end, or before the beginning, of the intended buffer. In Stackvector, 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

StackVec::extend used the lower and upper bounds from an Iterator's size_hint to determine how many items to push into the stack based vector. If the size_hint implementation returned a lower bound that was larger than the upper bound, StackVec would write out of bounds and overwrite memory on the stack. As mentioned by the size_hint documentation, size_hint is mainly for optimization and incorrect implementations should not lead to memory safety issues.

CVE-2021-29939 Affected Stackvector Versions

1 component(s)
Fixed Versions:
1.0.9
Product / Package Ecosystem Affected Versions Fixed Version
stackvector
 crates.io
< 1.0.9
1.0.9

References

NVD — CVE-2021-29939 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-29939
Stackvector Source Repository REPOSITORY
https://github.com/Alexhuszagh/rust-stackvector/issues/2
Stackvector Source Repository REPOSITORY
https://github.com/Alexhuszagh/rust-stackvector
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0048.html

Frequently Asked Questions

What is CVE-2021-29939?
CVE-2021-29939 is a security vulnerability in Stackvector involving Out of bounds write in stackvector under CWE-787: Out-of-bounds Write.
Which Stackvector versions are affected?
Affected versions include releases prior to 1.0.9 across affected packages: stackvector.
What version fixes CVE-2021-29939?
Upgrading to 1.0.9 (or the latest patched release for your respective branch) resolves the vulnerability.
Is stackvector affected?
Yes, stackvector is affected in releases prior to 1.0.9. Upgrade your dependency to 1.0.9 or later.
What is the CVSS score of CVE-2021-29939?
CVE-2021-29939 has a CVSS v3.1 base score of 7.3 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2021-29939?
CVE-2021-29939 is classified under CWE-787: Out-of-bounds Write (The product writes data past the end, or before the beginning, of the intended buffer.).
How can I check crates.io dependencies for CVE-2021-29939?
Run the dependency tree command: 'inspect dependencies for stackvector'. 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-9frf-r7c7-j2vg",
  "modified" : "2023-06-13T20:54:15Z",
  "published" : "2021-08-25T20:54:14Z",
  "aliases" : [ "CVE-2021-29939" ],
  "summary" : "Out of bounds write in stackvector",
  "details" : "StackVec::extend used the lower and upper bounds from an Iterator's size_hint to determine how many items to push into the stack based vector. If the size_hint implementation returned a lower bound that was larger than the upper bound, StackVec would write out of bounds and overwrite memory on the stack. As mentioned by the size_hint documentation, size_hint is mainly for optimization and incorrect implementations should not lead to memory safety issues.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "stackvector"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.0.9"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-29939"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Alexhuszagh/rust-stackvector/issues/2"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Alexhuszagh/rust-stackvector"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0048.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-787" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-19T17:15:11Z",
    "nvd_published_at" : "2021-04-01T05:15:00Z"
  }
}