🛡️ CVE-2026-27137 — go

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-295 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Incorrect enforcement of email constraints in crypto/x509

When verifying a certificate chain which contains a certificate containing multiple email address constraints which share common local portions but different domain portions, these constraints will not be properly applied, and only the last constraint will be considered.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2026-27137 is classified as CWE-295: Improper Certificate Validation. A TLS certificate is accepted without proper verification, so a man-in-the-middle can present their own.

Affected software

CVE-2026-27137 is recorded against 3 packages.

  • go
  • golang
  • stdlib

Timeline and source

Published on 6 March 2026 and last revised on 10 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

go.dev
go.dev
groups.google.com
pkg.go.dev
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com

CVE-2026-27137 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-295
Public Exploit ✅ No
Source NVD
Published 2026-03-06
Updated 2026-08-12
Modified 2026-08-10
Fix URL N/A

Affected Packages

Software From version Fixed in
go
golang
stdlib

References

Site Security Check

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