What is CVE-2026-5188?

CVE-2026-5188 is a high-severity vulnerability in Wolfssl, classified under Integer Underflow. CVSS score: 8.1/10. Published 2026-04-10.

How severe is CVE-2026-5188?

High severity. CVSS v3 base score is 8.1 out of 10.

Integer overflow in Wolfssl

CVE-2026-5188

An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This results in incorrect handling of certificate data. The issue is limited to configurations using the original ASN.1 parsing implementation which is off by default.

EPSS: 0.001 (3.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H.

Affected products

Wolfssl — versions 0

Weakness classification (CWE)

CWE-191 — Integer Underflow

References

facts@wolfssl.com (Patch, Issue Tracking)

Frequently asked questions

What is CVE-2026-5188?: CVE-2026-5188 is a high-severity vulnerability in Wolfssl, classified under Integer Underflow. CVSS score: 8.1/10. Published 2026-04-10.
How severe is CVE-2026-5188?: High severity. CVSS v3 base score is 8.1 out of 10.