CVE-2026-27145

(*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.
References
Link Resource
https://go.dev/cl/783621
https://go.dev/issue/79694
https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw
https://pkg.go.dev/vuln/GO-2026-5037
https://access.redhat.com/errata/RHSA-2026:23262
https://access.redhat.com/errata/RHSA-2026:23264
https://access.redhat.com/errata/RHSA-2026:29981
https://access.redhat.com/errata/RHSA-2026:33574
https://access.redhat.com/errata/RHSA-2026:34357
https://access.redhat.com/errata/RHSA-2026:34359
https://access.redhat.com/errata/RHSA-2026:35832
https://access.redhat.com/errata/RHSA-2026:36317
https://access.redhat.com/errata/RHSA-2026:36648
https://access.redhat.com/errata/RHSA-2026:36797
https://access.redhat.com/errata/RHSA-2026:38995
https://access.redhat.com/errata/RHSA-2026:39005
https://access.redhat.com/errata/RHSA-2026:39573
https://access.redhat.com/errata/RHSA-2026:39879
https://access.redhat.com/errata/RHSA-2026:41030
https://access.redhat.com/errata/RHSA-2026:41036
https://access.redhat.com/errata/RHSA-2026:41930
https://access.redhat.com/errata/RHSA-2026:42043
https://access.redhat.com/errata/RHSA-2026:42047
https://access.redhat.com/errata/RHSA-2026:42049
https://access.redhat.com/errata/RHSA-2026:42050
https://access.redhat.com/errata/RHSA-2026:42051
https://access.redhat.com/errata/RHSA-2026:42079
https://access.redhat.com/errata/RHSA-2026:42080
https://access.redhat.com/errata/RHSA-2026:42082
https://access.redhat.com/errata/RHSA-2026:42142
https://access.redhat.com/errata/RHSA-2026:42150
https://access.redhat.com/errata/RHSA-2026:42151
https://access.redhat.com/errata/RHSA-2026:42240
https://access.redhat.com/errata/RHSA-2026:42644
https://access.redhat.com/errata/RHSA-2026:42946
https://access.redhat.com/security/cve/CVE-2026-27145
https://bugzilla.redhat.com/show_bug.cgi?id=2484207
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27145.json
Configurations

No configuration.

History

22 Jul 2026, 19:10

Type Values Removed Values Added
Summary
  • (es) (x509.Certificate).VerifyHostname previamente llamaba a matchHostnames en un bucle sobre todas las entradas de Nombres Alternativos del Sujeto (SAN) de DNS. Esto provocó que strings.Split(host, ".") se ejecutara repetidamente en el mismo nombre de host de entrada. Con una lista SAN de DNS grande, los costos de verificación escalaron cuadráticamente en función del número de entradas SAN multiplicado por el recuento de etiquetas del nombre de host. Debido a que x509.Verify valida los nombres de host antes de construir la cadena de certificados, esta sobrecarga ocurría incluso para certificados no confiables.

22 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:42946 -

21 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:42043 -
  • () https://access.redhat.com/errata/RHSA-2026:42047 -
  • () https://access.redhat.com/errata/RHSA-2026:42049 -
  • () https://access.redhat.com/errata/RHSA-2026:42050 -
  • () https://access.redhat.com/errata/RHSA-2026:42051 -
  • () https://access.redhat.com/errata/RHSA-2026:42079 -
  • () https://access.redhat.com/errata/RHSA-2026:42080 -
  • () https://access.redhat.com/errata/RHSA-2026:42082 -
  • () https://access.redhat.com/errata/RHSA-2026:42142 -
  • () https://access.redhat.com/errata/RHSA-2026:42150 -
  • () https://access.redhat.com/errata/RHSA-2026:42151 -
  • () https://access.redhat.com/errata/RHSA-2026:42240 -
  • () https://access.redhat.com/errata/RHSA-2026:42644 -

20 Jul 2026, 12:18

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:41930 -

17 Jul 2026, 13:18

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:41030 -
  • () https://access.redhat.com/errata/RHSA-2026:41036 -

16 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:23262 -
  • () https://access.redhat.com/errata/RHSA-2026:23264 -
  • () https://access.redhat.com/errata/RHSA-2026:39879 -

15 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:39573 -

14 Jul 2026, 12:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:38995 -
  • () https://access.redhat.com/errata/RHSA-2026:39005 -

09 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:29981 -
  • () https://access.redhat.com/errata/RHSA-2026:36797 -

08 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:36317 -
  • () https://access.redhat.com/errata/RHSA-2026:36648 -

06 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:35832 -

02 Jul 2026, 12:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:34357 -
  • () https://access.redhat.com/errata/RHSA-2026:34359 -

01 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:33574 -

30 Jun 2026, 03:17

Type Values Removed Values Added
CWE CWE-606
References
  • () https://access.redhat.com/security/cve/CVE-2026-27145 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2484207 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27145.json -

04 Jun 2026, 14:16

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 6.5

02 Jun 2026, 23:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-06-02 23:16

Updated : 2026-07-22 19:10


NVD link : CVE-2026-27145

Mitre link : CVE-2026-27145

CVE.ORG link : CVE-2026-27145


JSON object : View

Products Affected

No product.

CWE
CWE-606

Unchecked Input for Loop Condition