{"schema_version":"1.3.1","id":"GO-2026-4866","modified":"2026-04-07T22:53:49Z","published":"2026-04-07T22:53:49Z","aliases":["CVE-2026-33810"],"summary":"Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509","details":"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.\n\nThis 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":[{"package":{"name":"stdlib","ecosystem":"Go"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.26.0-0"},{"fixed":"1.26.2"}]}],"ecosystem_specific":{"imports":[{"path":"crypto/x509","symbols":["Certificate.Verify","dnsConstraints.query","newDNSConstraints"]}]}}],"references":[{"type":"FIX","url":"https://go.dev/cl/763763"},{"type":"REPORT","url":"https://go.dev/issue/78332"},{"type":"WEB","url":"https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU"}],"credits":[{"name":"Riyas from Saintgits College of Engineering"},{"name":"k1rnt"},{"name":"@1seal"}],"database_specific":{"url":"https://pkg.go.dev/vuln/GO-2026-4866","review_status":"REVIEWED"}}