CVE-2021-45695: Mopa Incorrect Reliance On Trait Memory Vulnerability

CRITICAL
Advisory Identifier: GHSA-2gxj-qrp2-53jv
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CVSS 9.8
Published
Advisory Summary

CVE-2021-45695 is a CRITICAL (CVSS 9.8) incorrect reliance on trait memory vulnerability (General Security Weakness) affecting Mopa libraries in the crates.io ecosystem. The issue involves incorrect reliance on trait memory layout in mopa. Remediation is available in the latest vendor maintenance releases.

CVE-2021-45695 at a Glance

CVE Identifier CVE-2021-45695
GHSA Identifier GHSA-2gxj-qrp2-53jv
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification General Security Weakness
Affected Product Mopa
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-2021-45695

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

mopa fixed: Latest secure release 
Upgrade mopa 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 mopa

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-45695, inspect your project dependencies for Mopa:

inspect dependencies for mopa

Analyze the terminal output to locate any version of Mopa 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 General Security Weakness. In Mopa, 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 mopa crate redefines the deprecated TraitObject struct from core::raw. This is done to then transmute a reference to a trait object (&dyn Trait for any trait Trait) into this struct and retrieve the data field for the purpose of downcasting. This is used to implement downcast_ref_unchecked(), in terms of which downcast_ref() is also implemented. Same goes for mutable reference downcasting and Box downcasting. The Rust compiler explicitly reserves the right to change the memory layout of &dyn Trait for any trait Trait. The worst case scenario is that it swaps data and vtable, making an executable location breach and compromisation of ASLR possible, since reads from data would read vtable instead. Likewise, arbitrary code execution is also theoretically possible if reads of vtable generated by the compiler read data instead.

CVE-2021-45695 Affected Mopa Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
mopa
 crates.io
≤ 0.2.2

References

NVD — CVE-2021-45695 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-45695
Mopa Source Repository REPOSITORY
https://github.com/chris-morgan/mopa/issues/13
Mopa Source Repository REPOSITORY
https://github.com/chris-morgan/mopa
raw.githubusercontent.com/rustsec/advisory-db... WEB
https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/mopa/RUSTSEC-2021-0095.md
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2021-0095.html

Frequently Asked Questions

What is CVE-2021-45695?
CVE-2021-45695 is a security vulnerability in Mopa involving Incorrect reliance on Trait memory layout in mopa under General Security Weakness.
Which Mopa versions are affected?
Affected versions include releases prior to current release patches across affected packages: mopa.
What version fixes CVE-2021-45695?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is mopa affected?
Yes, mopa 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-2021-45695?
CVE-2021-45695 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-2021-45695?
CVE-2021-45695 is classified under General Security Weakness.
How can I check crates.io dependencies for CVE-2021-45695?
Run the dependency tree command: 'inspect dependencies for mopa'. 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-2gxj-qrp2-53jv",
  "modified" : "2023-06-13T18:34:26Z",
  "published" : "2022-01-06T22:11:11Z",
  "aliases" : [ "CVE-2021-45695" ],
  "summary" : "Incorrect reliance on Trait memory layout in mopa",
  "details" : "The mopa crate redefines the deprecated TraitObject struct from core::raw. This is done to then transmute a reference to a trait object (&dyn Trait for any trait Trait) into this struct and retrieve the data field for the purpose of downcasting. This is used to implement downcast_ref_unchecked(), in terms of which downcast_ref() is also implemented. Same goes for mutable reference downcasting and Box downcasting.\n\nThe Rust compiler explicitly reserves the right to change the memory layout of &dyn Trait for any trait Trait. The worst case scenario is that it swaps data and vtable, making an executable location breach and compromisation of ASLR possible, since reads from data would read vtable instead. Likewise, arbitrary code execution is also theoretically possible if reads of vtable generated by the compiler read data instead.",
  "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" : "mopa"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.2.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-45695"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/chris-morgan/mopa/issues/13"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/chris-morgan/mopa"
  }, {
    "type" : "WEB",
    "url" : "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/mopa/RUSTSEC-2021-0095.md"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2021-0095.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-01-06T14:22:40Z",
    "nvd_published_at" : "2021-12-27T00:15:00Z"
  }
}