Cyber Resilience

CVE-2021-4238

CriticalPublic PoC

Published: 27 December 2022

Published
27 December 2022
Modified
11 April 2025
KEV Added
Patch
CVSS Score v3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS Score 0.0034 56.8th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-4238 is a critical-severity Insufficient Entropy (CWE-331) vulnerability in Goutils Project Goutils. Its CVSS base score is 9.1 (Critical).

Operationally, ranked in the top 43.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Randomly-generated alphanumeric strings contain significantly less entropy than expected. The RandomAlphaNumeric and CryptoRandomAlphaNumeric functions always return strings containing at least one digit from 0 to 9. This significantly reduces the amount of entropy in short strings generated by these functions.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

goutils project
goutils
≤ 1.1.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-331

Approved key-establishment methods mandate sufficient entropy during key generation, eliminating entropy-starved keys.

References