CVE-2021-3692: Yiisoft/yii2 dev Use Of Cryptographically Weak Pseudo-Random Vulnerability

MODERATE
Advisory Identifier: GHSA-wwvv-x5mq-h3jj
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CVSS 5.3
CWE-338 CWE-330
Published
Advisory Summary

CVE-2021-3692 is a MODERATE (CVSS 5.3) use of cryptographically weak pseudo-random vulnerability (CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)) affecting Yiisoft/yii2 dev libraries in the Packagist ecosystem. The issue involves use of cryptographically weak pseudo-random number generator in yiisoft/yii2-dev. Remediation is available by upgrading affected packages to version 2.0.43.

CVE-2021-3692 at a Glance

CVE Identifier CVE-2021-3692
GHSA Identifier GHSA-wwvv-x5mq-h3jj
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Affected Product Yiisoft/yii2 dev
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.3

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:N/A:N).

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 None (I:N)
Availability None (A:N)

How to Fix CVE-2021-3692

To remediate this vulnerability, upgrade all affected Yiisoft/yii2 dev dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

yiisoft/yii2-dev fixed: 2.0.43 
Upgrade yiisoft/yii2-dev to 2.0.43
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 yiisoft/yii2-dev

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-3692, inspect your project dependencies for Yiisoft/yii2 dev:

inspect dependencies for yiisoft/yii2-dev

Analyze the terminal output to locate any version of Yiisoft/yii2 dev in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.43), 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-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG), where the product uses a pseudo-random number generator (prng) in a security context, but the prng's algorithm is not cryptographically strong. In Yiisoft/yii2 dev, 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

yii2 is vulnerable to Use of Predictable Algorithm in Random Number Generator

CVE-2021-3692 Affected Yiisoft/yii2 dev Versions

1 component(s)
Fixed Versions:
2.0.43
Product / Package Ecosystem Affected Versions Fixed Version
yiisoft/yii2-dev
 Packagist
< 2.0.43
2.0.43

References

NVD — CVE-2021-3692 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3692
Security Fix Commit FIX COMMIT
https://github.com/yiisoft/yii2/commit/13f27e4d920a05d53236139e8b07007acd046a46
Yiisoft/yii2 dev Source Repository REPOSITORY
https://github.com/yiisoft/yii2
huntr.dev/bounties/55517f19-5... WEB
https://huntr.dev/bounties/55517f19-5c28-4db2-8b00-f78f841e8aba

Frequently Asked Questions

What is CVE-2021-3692?
CVE-2021-3692 is a security vulnerability in Yiisoft/yii2 dev involving Use of Cryptographically Weak Pseudo-Random Number Generator in yiisoft/yii2-dev under CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG).
Which Yiisoft/yii2 dev versions are affected?
Affected versions include releases prior to 2.0.43 across affected packages: yiisoft/yii2-dev.
What version fixes CVE-2021-3692?
Upgrading to 2.0.43 (or the latest patched release for your respective branch) resolves the vulnerability.
Is yiisoft/yii2-dev affected?
Yes, yiisoft/yii2-dev is affected in releases prior to 2.0.43. Upgrade your dependency to 2.0.43 or later.
What is the CVSS score of CVE-2021-3692?
CVE-2021-3692 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2021-3692?
CVE-2021-3692 is classified under CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.).
How can I check Packagist dependencies for CVE-2021-3692?
Run the dependency tree command: 'inspect dependencies for yiisoft/yii2-dev'. 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-wwvv-x5mq-h3jj",
  "modified" : "2021-08-30T20:28:42Z",
  "published" : "2021-09-01T18:35:26Z",
  "aliases" : [ "CVE-2021-3692" ],
  "summary" : "Use of Cryptographically Weak Pseudo-Random Number Generator in yiisoft/yii2-dev",
  "details" : "yii2 is vulnerable to Use of Predictable Algorithm in Random Number Generator",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "yiisoft/yii2-dev"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.0.43"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3692"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yiisoft/yii2/commit/13f27e4d920a05d53236139e8b07007acd046a46"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/yiisoft/yii2"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.dev/bounties/55517f19-5c28-4db2-8b00-f78f841e8aba"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-330", "CWE-338" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-30T20:28:42Z",
    "nvd_published_at" : "2021-08-10T17:15:00Z"
  }
}