VulnerabilityAnalyzed

CVE-2026-5188

An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates.

LOW 2.3EPSS 0.14%

Does this matter?

Lower severity and a low EPSS score (0.14%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 4.0: 2.3 LOWCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.14% probability · 3th percentile
CISA KEV: Not listed
Weakness: CWE-191
Affected: wolfssl/wolfssl
Source: facts@wolfssl.com

References

https://github.com/wolfSSL/wolfssl/pull/10024Issue Tracking, Patch

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.