Improper Authorization in Go programming language - CVE-2026-27137

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Main Vulnerability Database Vulnerabilities #VU124115

Improper Authorization in Go programming language - CVE-2026-27137

Published: March 19, 2026


Vulnerability identifier: #VU124115
CSH Severity: Medium
CVSS v4 BT: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2026-27137
CWE-ID: CWE-285
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass email address constraints during X.509 certificate chain verification.

The vulnerability exists due to improper enforcement of email constraints in crypto/x509 when verifying certificate chains containing multiple email address constraints with shared local parts but different domains. A remote attacker can present a certificate chain with malformed email constraints to cause only the last constraint to be applied, leading to improper validation.

This issue only affects Go 1.26 and requires the certificate chain to chain to a trusted root. A trusted CA must issue the malicious certificate.


Affected software

Go programming language
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
Anolis OS
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Development Tools Module
openSUSE Leap
rhc-worker-playbook (Red Hat package)
delve (Red Hat package)
go1.26-openssl
go1.26-openssl-doc
go1.26-openssl-race
go1.26-doc
go1.26
go1.26-race
etcd (Red Hat package)
image-builder (Red Hat package)
osbuild-composer
osbuild-composer-core
osbuild-composer-worker
OpenShift Logging
App Connect Enterprise Certified Container
Red Hat OpenStack

How to mitigate CVE-2026-27137

Install security update from vendor's website.

Go programming language - update to 1.26.1
rhc-worker-playbook (Red Hat package) - addressed in versions 0.2.3-4.el10_0, 0.2.3-4.el10_1
delve (Red Hat package) - update to 1.25.2-3.el10_1
go1.26-openssl - addressed in versions 1.26.1-150000.1.3.1, 1.26.1-150600.13.3.1
go1.26-openssl-doc - addressed in versions 1.26.1-150000.1.3.1, 1.26.1-150600.13.3.1
go1.26-openssl-race - addressed in versions 1.26.1-150000.1.3.1, 1.26.1-150600.13.3.1
go1.26-doc - update to 1.26.1-150000.1.6.1
go1.26 - update to 1.26.1-150000.1.6.1
go1.26-race - update to 1.26.1-150000.1.6.1
etcd (Red Hat package) - update to 3.4.26-9.5.el9ost
OpenShift Logging - update to 6.0.15
App Connect Enterprise Certified Container - addressed in versions 12.0.22, 13.0.0
Red Hat OpenStack - update to 17.1
image-builder (Red Hat package) - update to 52.1-1.el10_2
osbuild-composer - update to 149-5
osbuild-composer-core - update to 149-5
osbuild-composer-worker - update to 149-5

External References

Related Security Bulletins