CVE-2026-27145 | BDVDB-2026-337277 Detail
Go standard librarycrypto/x509
Description#
(*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.
Impact#
Per CVSS v3.1: confidentiality impact none, integrity impact low, availability impact high. Attack vector: network.
Weaknesses#
References#
- 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/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
- https://access.redhat.com/errata/RHSA-2026:42079
- https://access.redhat.com/errata/RHSA-2026:42080
- https://access.redhat.com/errata/RHSA-2026:68334
- https://access.redhat.com/errata/RHSA-2026:68335
- https://access.redhat.com/errata/RHSA-2026:53416
- https://access.redhat.com/errata/RHSA-2026:50319
- https://access.redhat.com/errata/RHSA-2026:54757
- https://access.redhat.com/errata/RHSA-2026:57482
Show all 40
- https://access.redhat.com/errata/RHSA-2026:42082
- 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-2026:49703
- https://access.redhat.com/errata/RHSA-2026:49702
- https://access.redhat.com/errata/RHSA-2026:53413
- https://access.redhat.com/errata/RHSA-2026:53374
- https://access.redhat.com/errata/RHSA-2026:54168
- https://access.redhat.com/errata/RHSA-2026:51187
- https://access.redhat.com/errata/RHSA-2026:46394
- https://access.redhat.com/errata/RHSA-2026:46395
- https://access.redhat.com/errata/RHSA-2026:29980
- https://access.redhat.com/errata/RHSA-2026:35832
- https://access.redhat.com/errata/RHSA-2026:34357
- https://access.redhat.com/errata/RHSA-2026:39005
- https://access.redhat.com/errata/RHSA-2026:42946
- https://access.redhat.com/errata/RHSA-2026:39573
- https://access.redhat.com/errata/RHSA-2026:38995
- https://access.redhat.com/errata/RHSA-2026:41930
- https://access.redhat.com/errata/RHSA-2026:61253
- https://access.redhat.com/errata/RHSA-2026:60354
- https://access.redhat.com/errata/RHSA-2026:57649
- https://access.redhat.com/errata/RHSA-2026:53412
- https://access.redhat.com/errata/RHSA-2026:60315
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.