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GO-2026-4866

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.

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.

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Affected packages

Go / stdlib
Introduced in: 1.26.0-0 Fixed in: 1.26.2
Fix go get stdlib@v1.26.2

References