Is CVE-2026-5188 in the CISA KEV catalog?

No. CVE-2026-5188 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-5188?

CVE-2026-5188 has a CVSS v3 base score of 8.1 (Low).

What is the EPSS score for CVE-2026-5188?

CVE-2026-5188 has an EPSS score of 0.14% (3th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-5188?

Upgrade wolfssl on debian unstable to 5.9.1-0.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-5188

LOW

8.1

CVSS v3

NVD

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.

CWE-191

How to fix

Remediation Available

wolfsslDebian

Fixed in:5.9.1-0.1CVE-2026-5188

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Exploit Intelligence

0.14%probability of exploitation in 30 days

3rdpercentile

Low risk: more likely to be exploited than 3% of all known CVEs.

References

Patch1

github.com

Related Vulnerabilities

Other CWE-191 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0497	Critical	9.8	100%	KEV	Fix
CVE-2020-36221	High	7.5	84%	-	Fix
CVE-2020-36228	High	7.5	83%	-	Fix
CVE-2023-31102	High	7.8	71%	-	Fix
CVE-2024-38063	Critical	9.8	71%	-	Fix
CVE-2017-14496	High	7.5	66%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.