CVE-2026-33810

Description

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.

PUBLISHED Reserved 2026-03-23 | Published 2026-04-08 | Updated 2026-04-20 | Assigner Go

Problem types

CWE-295: Improper Certificate Validation

Product status

Credits

Riyas from Saintgits College of Engineering

k1rnt

@1seal

References

www.openwall.com/lists/oss-security/2026/04/19/4

www.openwall.com/lists/oss-security/2026/04/20/1

go.dev/cl/763763

go.dev/issue/78332

groups.google.com/g/golang-announce/c/0uYbvbPZRWU

pkg.go.dev/vuln/GO-2026-4866

cve.org (CVE-2026-33810)

nvd.nist.gov (CVE-2026-33810)

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