CVE-2026-27145mediumCWE-606

CVE-2026-27145: falha de média gravidade em Go standard library crypto/x509

Inefficient candidate hostname parsing in crypto/x509

Publicada em 02 jun 2026 · Atualizada em 18 set 2026

33Vexday Risk Score

Sem sinal de exploração. Ela tem prova de conceito pública.

ssvc Attendcvss 6.5epss 0.6%

da publicação à arma1 dias

Publicada no NVD2 de jun.

1ª PoC+1d

probabilidade de exploração

0.6%top 53% das CVEs

exploração observada

nãonenhuma fonte reporta

1 exploit(s) público(s)

(*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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

Produtos afetados

Go standard library · crypto/x509

PoCs públicas encontradas — 1

githubgithub.com/HORKimhab/CVE-2026-27145★ 0

⚠ Recursos públicos, para você avaliar a exposição de sistemas que controla ou está autorizado a testar. Teste apenas com autorização.

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Referências