Vulnerabilidades do Go standard library Crypto/x509

CVE-2026-27145 Média · 6.5 CWE-606 02/06/2026

Inefficient candidate hostname parsing in crypto/x509

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

CVE-2026-33810 Alta · 8.2 CWE-295 07/04/2026

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

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.

CVE-2026-32281 Alta · 7.5 CWE-295 07/04/2026

Inefficient policy validation in crypto/x509

Validating certificate chains which use policies is unexpectedly inefficient when certificates in the chain contain a very large number of policy mappings, possibly causing denial of service. 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.

CVE-2026-32280 Alta · 7.5 CWE-770 07/04/2026

Unexpected work during chain building in crypto/x509

During chain building, the amount of work that is done is not correctly limited when a large number of intermediate certificates are passed in VerifyOptions.Intermediates, which can lead to a denial of service. This affects both direct users of crypto/x509 and users of crypto/tls.

CVE-2026-27138 Média · 5.9 CWE-295 06/03/2026

Panic in name constraint checking for malformed certificates in crypto/x509

Certificate verification can panic when a certificate in the chain has an empty DNS name and another certificate in the chain has excluded name constraints. This can crash programs that are either directly verifying X.509 certificate chains, or those that use TLS.

CVE-2026-27137 Alta · 7.5 CWE-295 06/03/2026

Incorrect enforcement of email constraints in crypto/x509

When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered.

CVE-2025-61727 Média · 6.5 CWE-295 03/12/2025

Improper application of excluded DNS name constraints when verifying wildcard names in crypto/x509

An excluded subdomain constraint in a certificate chain does not restrict the usage of wildcard SANs in the leaf certificate. For example a constraint that excludes the subdomain test.example.com does not prevent a leaf certificate from claiming the SAN *.example.com.

CVE-2025-61729 Alta · 7.5 CWE-295 02/12/2025

Excessive resource consumption when printing error string for host certificate validation in crypto/x509

Within HostnameError.Error(), when constructing an error string, there is no limit to the number of hosts that will be printed out. Furthermore, the error string is constructed by repeated string concatenation, leading to quadratic runtime. Therefore, a certificate provided by a malicious actor can result in excessive resource consumption.

CVE-2025-58188 Alta · 7.5 CWE-295 29/10/2025

Panic when validating certificates with DSA public keys in crypto/x509

Validating certificate chains which contain DSA public keys can cause programs to panic, due to a interface cast that assumes they implement the Equal method. This affects programs which validate arbitrary certificate chains.

CVE-2025-58187 Alta · 7.5 CWE-407 29/10/2025

Quadratic complexity when checking name constraints in crypto/x509

Due to the design of the name constraint checking algorithm, the processing time of some inputs scale non-linearly with respect to the size of the certificate. This affects programs which validate arbitrary certificate chains.