Error Handling in Go programming language - CVE-2026-27138
Published: March 19, 2026
Vulnerability identifier: #VU124116
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-27138
CWE-ID: CWE-388
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Google
Affected software:
Go programming language
Go programming language
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service via application crash during X.509 certificate verification.
The vulnerability exists due to a panic in name constraint checking in crypto/x509 when processing a certificate chain containing a certificate with an empty DNS name and another certificate with excluded name constraints. A remote attacker can send a specially crafted certificate chain to trigger a panic during verification.
This issue only affects Go 1.26 and requires the certificate chain to chain to a trusted root. A trusted CA must issue the malformed certificate.
How to mitigate CVE-2026-27138
Install security update from vendor's website.