# CVE-2021-3990: showdoc is vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Source: https://junglewise.ai/threats/cve-2021-3990-showdoc-is-vulnerable-to-use-of-cryptographically-weak-pseudo  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-12-03  
License: CC BY 4.0 with a link back

CVE-2021-3990 · Severity: low · CVSS 3.1 · Published 2021-12-03

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

Technologies: [showdoc/showdoc (Packagist)](https://junglewise.ai/threats/technologies/showdoc-showdoc). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2021-3990 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-3990 being exploited in the wild.

**How severe is CVE-2021-3990?** Low severity, with a CVSS score of 3.1, published 3 December 2021.

**Which products and versions are affected?** showdoc/showdoc (Packagist) ECOSYSTEM:introduced=0,fixed=2.9.13.

**Is there a fix for CVE-2021-3990?** Yes. showdoc/showdoc (Packagist): upgrade to 2.9.13 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-3990?** Check whether you run showdoc/showdoc (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- showdoc/showdoc (Packagist): upgrade to 2.9.13 or later

  ```sh
  composer require showdoc/showdoc:^2.9.13
  ```


## Affected products

- showdoc/showdoc (Packagist) ECOSYSTEM:introduced=0,fixed=2.9.13

## Identifiers

- CVE-2021-3990
- GHSA-vrgh-5w3c-ggf8

## Related threats

- [ShowDoc has an Injection vulnerability](https://junglewise.ai/threats/cve-2026-6982-showdoc-has-an-injection-vulnerability)
- [ShowDoc unrestricted file upload vulnerability](https://junglewise.ai/threats/cve-2025-0520-showdoc-unrestricted-file-upload-vulnerability)
- [Showdoc XSS Vulnerability](https://junglewise.ai/threats/cve-2018-16342-showdoc-xss-vulnerability)
- [Showdoc Forced Browsing](https://junglewise.ai/threats/cve-2018-19609-showdoc-forced-browsing)
- [Showdoc CSRF Vulnerability](https://junglewise.ai/threats/cve-2018-19621-showdoc-csrf-vulnerability)