What’s Vulnerable › Vulnerabilities

CVE-2026-5263: URI nameConstraints not enforced in ConfirmNameConstraints()

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-09 · updated 2026-07-02
• Weakness: CWE-295

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.

Affected products

• wolfSSL: before 5.9.1 — fixed in 5.9.1

How to fix

Upgrade to a fixed version: wolfSSL 5.9.1. Check the vendor advisory for mitigations.

References

• https://github.com/wolfSSL/wolfssl/pull/10048
• https://www.talosintelligence.com/vulnerability_reports/TALOS-2026-2410

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