--- id: CVE-2026-33810 title: >- 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 summary: >- 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 ce… severity: high cvss: 8.2 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N' cwe: - CWE-295 - CWE-1289 vendor: golang product: go affected: - 'go >= 1.26.0, < 1.26.2' patched: - go 1.26.2 published: '2026-04-08' updated: '2026-09-18' sourceUpdated: '2026-09-18T13:17:56.113' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-33810' references: - url: 'https://go.dev/cl/763763' label: security@golang.org - url: 'https://go.dev/issue/78332' label: security@golang.org - url: 'https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU' label: security@golang.org - url: 'https://pkg.go.dev/vuln/GO-2026-4866' label: security@golang.org - url: 'http://www.openwall.com/lists/oss-security/2026/04/19/4' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'http://www.openwall.com/lists/oss-security/2026/04/20/1' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2026:10155' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - 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url: 'https://www.cve.org/CVERecord?id=CVE-2026-33810' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-33810' tags: - nvd - cve.org - csaf - vex - red-hat - osv - go epss: 0.0034 epssPercentile: 0.2469 aliases: - GO-2026-4866 - BIT-golang-2026-33810 ecosystem: go ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-04-13T17:48:57.879958Z' scores: nvd: 8.2 adp: 7.5 vendor: 8.8 ingestedAt: '2026-07-01T03:50:34.554Z' --- ## Overview 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. ## Affected - `go >= 1.26.0, < 1.26.2` ## Remediation Upgrade past the affected range: - `go 1.26.2` ## Package advisory (CVE-2026-33810) Affected packages: - `stdlib >= 1.26.0-0, < 1.26.2` Patched in: - `stdlib 1.26.2` Source: https://osv.dev/vulnerability/GO-2026-4866 ## Vendor advisories - **RHSA-2026:54757** · Red Hat · fixed in: Red Hat OpenStack Platform 16.2 · released 2026-08-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:54757) - **RHSA-2026:14391** · Red Hat · fixed in: Cryostat 4 on RHEL 9 · released 2026-05-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:14391) - **RHSA-2026:36796** · Red Hat · fixed in: RHEM 1.0 for RHEL 9 · released 2026-07-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:36796) - **RHSA-2026:28047** · Red Hat · fixed in: Red Hat OpenStack Platform 17.1 · released 2026-06-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:28047) - **RHSA-2026:39810** · Red Hat · fixed in: Red Hat OpenStack Services on OpenShift 18.0, 9Base-RHOSO-TOOLS-18 · released 2026-07-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:39810) - **RHSA-2026:34365** · Red Hat · fixed in: Red Hat Satellite 6.19 for RHEL 9 · released 2026-07-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:34365) - **RHSA-2026:49703** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-08-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:49703) - **RHSA-2026:49702** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-08-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:49702) - **RHSA-2026:56143** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-08-18 · [advisory](https://access.redhat.com/errata/RHSA-2026:56143) - **RHSA-2026:59546** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59546) - **RHSA-2026:19719** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-05-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:19719) - **Red Hat VEX** · Important · affected: Assisted Installer for Red Hat OpenShift Container Platform 2, cert-manager Operator for Red Hat OpenShift, Confidential Compute Attestation, Deployment Validation Operator, Fence Agents Remediation Operator, File Integrity Operator, … · no fix planned: Confidential Compute Attestation, Gatekeeper 3, Multicluster Engine for Kubernetes, Red Hat 3scale API Management Platform 2, … · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33810.json) - **RHSA-2026:67149** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:67149) - **RHSA-2026:67517** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-09-15 · [advisory](https://access.redhat.com/errata/RHSA-2026:67517) - **RHSA-2026:68334** · Red Hat · fixed in: RHEM 1.1 for RHEL 10, RHEM 1.1 for RHEL 9 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68334)