CVE-2026-33810highCWE-1289

CVE-2026-33810: high-severity vulnerability in Go standard library crypto/x509

Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Affected products
Go standard library · crypto/x509
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