How severe is CVE-2026-27138?

CVE-2026-27138 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-27138 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27138?

CVE-2026-27138 affects Golang Go. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27138?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-27138 have an EU (EUVD) identifier?

Yes. CVE-2026-27138 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10086.

When was CVE-2026-27138 published?

CVE-2026-27138 was published on 2026-03-06 and last updated on 2026-06-17.

CVE-2026-27138

CVE-2026-27138 is a medium-severity vulnerability in Golang Go with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10086
Weakness: CWE-295
Affected product: Golang Go
Published: 2026-03-06
Last modified: 2026-06-17

Description

Certificate verification can panic when a certificate in the chain has an empty DNS name and another certificate in the chain has excluded name constraints. This can crash programs that are either directly verifying X.509 certificate chains, or those that use TLS.

Frequently asked questions

What is CVE-2026-27138?: Certificate verification can panic when a certificate in the chain has an empty DNS name and another certificate in the chain has excluded name constraints. This can crash programs that are either directly verifying X.509 certificate chains, or those that use TLS.
How severe is CVE-2026-27138?: CVE-2026-27138 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-27138 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27138?: CVE-2026-27138 affects Golang Go. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27138?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27138 have an EU (EUVD) identifier?: Yes. CVE-2026-27138 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10086.
When was CVE-2026-27138 published?: CVE-2026-27138 was published on 2026-03-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:golang:go:1.26.0:*:*:*:*:*:*:*

More vulnerabilities in Golang Go

CVE-2025-68121 — Critical (CVSS 10.0): During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between…
CVE-2026-27143 — Critical (CVSS 9.8): Arithmetic over induction variables in loops were not correctly checked for underflow or overflow. As a result, the…
CVE-2024-24790 — Critical (CVSS 9.8): The various Is methods (IsPrivate, IsLoopback, etc) did not work as expected for IPv4-mapped IPv6 addresses, returning…
CVE-2023-39320 — Critical (CVSS 9.8): The go.mod toolchain directive, introduced in Go 1.21, can be leveraged to execute scripts and binaries relative to the…
CVE-2023-29405 — Critical (CVSS 9.8): The go command may execute arbitrary code at build time when using cgo. This may occur when running "go get" on a…
CVE-2023-29404 — Critical (CVSS 9.8): The go command may execute arbitrary code at build time when using cgo. This may occur when running "go get" on a…

All CVEs affecting Golang Go →

Other CWE-295 (Improper Certificate Validation) vulnerabilities

CVE-2026-4370 — Critical (CVSS 10.0): A vulnerability was identified in Juju from version 3.2.0 until 3.6.19 and from version 4.0 until 4.0.4, where the…
CVE-2026-30836 — Critical (CVSS 10.0): Step CA is an online certificate authority for secure, automated certificate management for DevOps. Versions 0.30.0-rc6…
CVE-2025-68121 — Critical (CVSS 10.0): During session resumption in crypto/tls, if the underlying Config has its ClientCAs or RootCAs fields mutated between…
CVE-2022-20703 — Critical (CVSS 10.0): Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker…
CVE-2021-1471 — Critical (CVSS 9.9): Multiple vulnerabilities in Cisco Jabber for Windows, Cisco Jabber for MacOS, and Cisco Jabber for mobile platforms…
CVE-2026-20184 — Critical (CVSS 9.8): A vulnerability in the integration of single sign-on (SSO) with Control Hub in Cisco Webex Services could have allowed…

Browse all CWE-295 (Improper Certificate Validation) vulnerabilities →