What is CVE-2021-38597?

CVE-2021-38597 is a medium-severity vulnerability in Wolfssl, classified under Insufficient Verification of Data Authenticity. CVSS score: 5.9/10. Published 2021-08-12.

How severe is CVE-2021-38597?

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

Vulnerability in Wolfssl

CVE-2021-38597

wolfSSL before 4.8.1 incorrectly skips OCSP verification in certain situations of irrelevant response data that contains the NoCheck extension.

Published 2021-08-12 · 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: 0.005 (39.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Wolfssl

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

www.wolfssl.com/docs/wolfssl-changelog/ (Release Notes, Vendor Advisory)
github.com/wolfSSL/wolfssl/commit/f93083be72a3b3d956b52a7ec13f307a27b6e093 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-38597?: CVE-2021-38597 is a medium-severity vulnerability in Wolfssl, classified under Insufficient Verification of Data Authenticity. CVSS score: 5.9/10. Published 2021-08-12.
How severe is CVE-2021-38597?: Medium severity. CVSS v3 base score is 5.9 out of 10.