Certificate Chain Verification Flaw in wolfSSL Impacts URI NameConstraints
CVE-2026-5263

7HIGH

Key Information:

Vendor

Wolfssl

Status
Wolfssl
Vendor
CVE Published:
9 April 2026

What is CVE-2026-5263?

A vulnerability exists in wolfSSL where nameConstraints from intermediate CAs are processed but not properly enforced during the certificate chain verification process. This flaw allows a compromised or malicious sub-CA to issue leaf certificates that may contain URI Subject Alternative Name (SAN) entries that violate the nameConstraints of the issuing CA, resulting in wolfSSL erroneously accepting these certificates as valid.

Affected Version(s)

wolfSSL 0 < 5.9.1

References

https://github.com/wolfSSL/wolfssl/pull/10048

CVSS V4

Score:
7
Severity:
HIGH
Confidentiality:
High
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Oleh Konko @1seal
.