CVE-2021-3678: Showdoc/showdoc Use Of Cryptographically Weak Pseudo-Random Vulnerability

MODERATE
Advisory Identifier: GHSA-j85q-whc9-g4p9
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CVSS 5.9
CWE-338
Published
Advisory Summary

CVE-2021-3678 is a MODERATE (CVSS 5.9) use of cryptographically weak pseudo-random vulnerability (CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)) affecting Showdoc/showdoc libraries in the Packagist ecosystem. The issue involves use of cryptographically weak pseudo-random number generator in showdoc. Remediation is available by upgrading affected packages to version 2.9.8.

CVE-2021-3678 at a Glance

CVE Identifier CVE-2021-3678
GHSA Identifier GHSA-j85q-whc9-g4p9
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
Affected Product Showdoc/showdoc
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2021-3678

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

showdoc/showdoc fixed: 2.9.8 
Upgrade showdoc/showdoc to 2.9.8
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 showdoc/showdoc

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-3678, inspect your project dependencies for Showdoc/showdoc:

inspect dependencies for showdoc/showdoc

Analyze the terminal output to locate any version of Showdoc/showdoc in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.9.8), 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 Showdoc/showdoc, 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

showdoc is vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

CVE-2021-3678 Affected Showdoc/showdoc Versions

1 component(s)
Fixed Versions:
2.9.8
Product / Package Ecosystem Affected Versions Fixed Version
showdoc/showdoc
 Packagist
< 2.9.8
2.9.8

References

NVD — CVE-2021-3678 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3678
Security Fix Commit FIX COMMIT
https://github.com/star7th/showdoc/commit/4b962c1740311e0d46775023b6acba39ad60e370
huntr.dev/bounties/f9a9defd-2... WEB
https://huntr.dev/bounties/f9a9defd-29ea-4442-b692-ff1512813de4

Frequently Asked Questions

What is CVE-2021-3678?
CVE-2021-3678 is a security vulnerability in Showdoc/showdoc involving Use of Cryptographically Weak Pseudo-Random Number Generator in showdoc under CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG).
Which Showdoc/showdoc versions are affected?
Affected versions include releases prior to 2.9.8 across affected packages: showdoc/showdoc.
What version fixes CVE-2021-3678?
Upgrading to 2.9.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is showdoc/showdoc affected?
Yes, showdoc/showdoc is affected in releases prior to 2.9.8. Upgrade your dependency to 2.9.8 or later.
What is the CVSS score of CVE-2021-3678?
CVE-2021-3678 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2021-3678?
CVE-2021-3678 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-2021-3678?
Run the dependency tree command: 'inspect dependencies for showdoc/showdoc'. 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-j85q-whc9-g4p9",
  "modified" : "2021-08-16T23:13:12Z",
  "published" : "2021-09-02T17:07:48Z",
  "aliases" : [ "CVE-2021-3678" ],
  "summary" : "Use of Cryptographically Weak Pseudo-Random Number Generator in showdoc",
  "details" : "showdoc is vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "showdoc/showdoc"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.9.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3678"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/star7th/showdoc/commit/4b962c1740311e0d46775023b6acba39ad60e370"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.dev/bounties/f9a9defd-29ea-4442-b692-ff1512813de4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-338" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-08-16T23:13:12Z",
    "nvd_published_at" : "2021-08-04T14:15:00Z"
  }
}