Is CVE-2026-5263 in the CISA KEV catalog?

No. CVE-2026-5263 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-5263?

CVE-2026-5263 has a CVSS v3 base score of 6.5 (Important).

What is the EPSS score for CVE-2026-5263?

CVE-2026-5263 has an EPSS score of 0.17% (6th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-5263?

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

CVE & CISA-KEV Catalog

CVE-2026-5263

HIGH

6.5

CVSS v3

NVD

Description

URI nameConstraints from constrained intermediate CAs are parsed but not enforced during certificate chain verification in wolfcrypt/src/asn.c. A compromised or malicious sub-CA could issue leaf certificates with URI SAN entries that violate the nameConstraints of the issuing CA, and wolfSSL would accept them as valid.

CWE-295Improper Certificate Validation

How to fix

Remediation Available

wolfsslDebian

Fixed in:5.9.1-0.1CVE-2026-5263

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 RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.17%probability of exploitation in 30 days

6thpercentile

Low risk: more likely to be exploited than 6% of all known CVEs.

References

Patch1

github.com

Other references1

talosintelligence.com

Related Vulnerabilities

Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-4000	Low	3.7	100%	-	Fix
CVE-2020-0601	High	8.1	89%	KEV	Fix
CVE-2009-3555	Critical	9.8	87%	-	Fix
CVE-2022-26923	High	8.8	83%	KEV	Fix
CVE-2023-27823	Critical	9.8	53%	-	-
CVE-2022-42979	High	8.8	24%	-	-

Embed a live status badge for CVE-2026-5263

Markdown

[![CVE-2026-5263](https://tridentstack.com/cve/badge/CVE-2026-5263.svg)](https://tridentstack.com/cve/CVE-2026-5263)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-5263"><img src="https://tridentstack.com/cve/badge/CVE-2026-5263.svg" alt="CVE-2026-5263"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

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 2026-07-02.