What is CVE-2026-6731?

CVE-2026-6731 is a high-severity vulnerability in Wolfssl, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2026-06-25.

How severe is CVE-2026-6731?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Wolfssl

CVE-2026-6731

X.509 name constraint bypass via the Subject Common Name when treated as a DNS-type name. A certificate whose Subject CN violates an issuing CA's DNS name constraints could be accepted.

Vulnerability class: Improper Certificate Validation

Published 2026-06-25 · last modified 2026-06-27.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.001 (1.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 1.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.001

Affected products

Wolfssl — versions 3.9.10

Weakness classification (CWE)

CWE-295 — Improper Certificate Validation

References

github.com/wolfSSL/wolfssl/pull/10223 (Patch, patch, Issue Tracking)
www.wolfssl.com/docs/security-vulnerabilities/ (Vendor Advisory)

Frequently asked questions

What is CVE-2026-6731?: CVE-2026-6731 is a high-severity vulnerability in Wolfssl, classified under Improper Certificate Validation. CVSS score: 7.5/10. Published 2026-06-25.
How severe is CVE-2026-6731?: High severity. CVSS v3 base score is 7.5 out of 10.