CVE-2026-33810: Golang Go

High severity, CVSS 8.2. EPSS: 0.3% chance of exploitation in the next 30 days.

When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.

Affected products

• Golang Go: from 1.26.0, before 1.26.2 (fixed in 1.26.2)

Published 2026-04-08. Last modified 2026-09-18.