How to fix CVE-2026-5263?

Within 24 hours: Identify all systems and applications using wolfSSL in production environments and document versions in use. Within 7 days: Implement enhanced certificate chain validation monitoring, enable Certificate Transparency log checking, and restrict intermediate CA issuance to highest-security environments only. Contact wolfSSL for patch timeline and subscribe to security advisories. Within 30 days: Evaluate migration to alternative cryptographic libraries with active URI nameConstraints support, or implement compensating controls via external certificate validation layers pending patch availability.

Is Wolfssl affected by CVE-2026-5263?

CVE-2026-5263 affects wolfSSL's certificate chain validation, allowing compromised intermediate CAs to issue certificates that violate URI nameConstraints restrictions, potentially enabling attackers to spoof trusted domains or bypass access controls.

CVE-2026-5263

EUVD-2026-21178 HIGH

2026-04-09 wolfSSL

7.0

CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Apr 09, 2026 - 21:45 vuln.today

EUVD ID Assigned

Apr 09, 2026 - 21:45 euvd

EUVD-2026-21178

CVE Published

Apr 09, 2026 - 21:15 nvd

HIGH 7.0

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.

Analysis

Certificate chain verification bypass in wolfSSL allows malicious intermediate CAs to violate URI nameConstraints. A compromised sub-CA with high-privilege access can issue leaf certificates containing URI Subject Alternative Name entries that breach parent CA nameConstraints restrictions. …

Remediation

Within 24 hours: Identify all systems and applications using wolfSSL in production environments and document versions in use. Within 7 days: Implement enhanced certificate chain validation monitoring, enable Certificate Transparency log checking, and restrict intermediate CA issuance to highest-security environments only. …

Analysis

Detailed AI-generated intelligence summary covering attack vector, impact assessment, affected versions, remediation steps, and indicators of compromise.

POChttps://••••••••••.com/exploit

PATCHhttps://••••••••••.com/patch

ADVISORYhttps://••••••••••.com/advisory

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Get intelligence summaries, risk assessment, exploit details, threat intel, and remediation guidance.

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +0.0

CVSS: +35

POC: 0

CVE-2026-5263 vulnerability details – vuln.today

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CVE-2026-5263

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CVE-2026-5263

CVSS Vector

Lifecycle Timeline

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