Certificate Chain Verification Issue in Go Programming Language
CVE-2026-33810

7.5HIGH

Key Information:

Vendor

Go Standard Library

Status
Crypto/x509
Vendor
CVE Published:
8 April 2026

What is CVE-2026-33810?

A vulnerability in the Go programming language arises when validating certificate chains that contain excluded DNS constraints. The issue manifests as incorrect application of these constraints to wildcard DNS Subject Alternative Names (SANs) when there is a case mismatch between the wildcard and the constraints. This flaw specifically affects the validation of otherwise trusted certificate chains, which are issued by a root Certificate Authority (CA) included in the specified CertPool or the system certificate pool.

Affected Version(s)

crypto/x509 1.26.0-0 < 1.26.2

References

https://go.dev/cl/763763
https://go.dev/issue/78332
https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Riyas from Saintgits College of Engineering
k1rnt
@1seal
.