What is CVE-2021-3678?

CVE-2021-3678 is a medium-severity vulnerability in Showdoc, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 5.9/10. Published 2021-08-04.

How severe is CVE-2021-3678?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Is CVE-2021-3678 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Showdoc

CVE-2021-3678

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

Published 2021-08-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.3th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Showdoc
Star7th Star7th/showdoc — versions unspecified

Weakness classification (CWE)

CWE-338 — Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Public proof-of-concept exploits

References

huntr.dev/bounties/f9a9defd-29ea-4442-b692-ff1512813de4 (Third Party Advisory)
github.com/star7th/showdoc/commit/4b962c1740311e0d46775023b6acba39ad60e370 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3678?: CVE-2021-3678 is a medium-severity vulnerability in Showdoc, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 5.9/10. Published 2021-08-04.
How severe is CVE-2021-3678?: Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2021-3678 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.