# CVE-2026-27137: Incorrect enforcement of email constraints in crypto/x509

CVE-2026-27137 is fixed in 24 products on 2 platforms, first by Go Programming Language 1.26.1, released March 5, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-27137
- Priority: High
- CVSS: 9.1 (Moderate)
- EPSS: 0.0066
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 6, 2026
- Weakness: CWE-295: Improper Certificate Validation
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27137

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Go Programming Language | 1.26.1 | [Go Programming Language 1.26.1](https://patchblox.com/security/data/fix/windows-app/golang.go-1.26.1.md) | Mar 5, 2026 |
| Linux | delve RHEL 10 | 1.26.1-1.el10_0 | [RHSA-2026:49703](https://patchblox.com/security/data/fix/linux/rhsa-2026-49703.md) | Apr 30, 2026 |
| Linux | delve almalinux 10 | 1.25.2-3.el10_1 | [ALSA-2026:8842](https://patchblox.com/security/data/fix/linux/alsa-2026-8842.md) | Apr 20, 2026 |
| Linux | delve ol 10 | 0:1.25.2-3.0.1.el10_1 | [ELSA-2026-8842](https://patchblox.com/security/data/fix/linux/elsa-2026-8842.md) | Apr 20, 2026 |
| Linux | delve rocky 10 | 0:1.25.2-3.el10_1 | [RLSA-2026:8842](https://patchblox.com/security/data/fix/linux/rlsa-2026-8842.md) | Apr 21, 2026 |
| Linux | flightctl RHEL 10 | 1.1.3-1.el10em | [RHSA-2026:41019](https://patchblox.com/security/data/fix/linux/rhsa-2026-41019.md) | May 22, 2026 |
| Linux | go-toolset RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | go-toolset almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | go-toolset almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | go-toolset ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | go-toolset ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | go1.26 opensuse-leap 15.6 | 1.26.1-150000.1.6.1 | [SUSE-SU-2026:0876-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0876-1.md) | Mar 11, 2026 |
| Linux | go1.26 opensuse-leap 16.0 | 1.26.1-160000.1.1 | [OPENSUSE-SU-2026:20342-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20342-1.md) | Mar 11, 2026 |
| Linux | go1.26 sles 15.6 | 1.26.1-150000.1.6.1 | [SUSE-SU-2026:0876-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0876-1.md) | Mar 11, 2026 |
| Linux | go1.26 sles 15.7 | 1.26.1-150000.1.6.1 | [SUSE-SU-2026:0876-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0876-1.md) | Mar 11, 2026 |
| Linux | go1.26-openssl opensuse-leap 15.6 | 1.26.1-150600.13.3.1 | [SUSE-SU-2026:0976-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0976-1.md) | Mar 23, 2026 |
| Linux | go1.26-openssl opensuse-leap 16.0 | 1.26.1-160000.1.1 | [OPENSUSE-SU-2026:20537-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20537-1.md) | Apr 14, 2026 |
| Linux | go1.26-openssl sles 15.6 | 1.26.1-150600.13.3.1 | [SUSE-SU-2026:0976-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0976-1.md) | Mar 23, 2026 |
| Linux | go1.26-openssl sles 15.7 | 1.26.1-150600.13.3.1 | [SUSE-SU-2026:0976-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-0976-1.md) | Mar 23, 2026 |
| Linux | go1.26-openssl sles 16.0 | 1.26.1-160000.1.1 | [SUSE-SU-2026:21195-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21195-1.md) | Apr 14, 2026 |
| Linux | golang RHEL 10 | 1.26.5-1.el10_0 | [RHSA-2026:49702](https://patchblox.com/security/data/fix/linux/rhsa-2026-49702.md) | May 27, 2026 |
| Linux | golang RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang rocky 10 | 0:1.26.2-2.el10_2 | [RLSA-2026:19022](https://patchblox.com/security/data/fix/linux/rlsa-2026-19022.md) | May 29, 2026 |
| Linux | golang rocky 9 | 0:1.26.2-1.el9_8 | [RLSA-2026:19181](https://patchblox.com/security/data/fix/linux/rlsa-2026-19181.md) | May 28, 2026 |
| Linux | golang-1.26 Debian 14 | 1.26.1-1 | [DEBIAN-CVE-2026-27137](https://patchblox.com/security/data/fix/linux/debian-cve-2026-27137.md) | Mar 6, 2026 |
| Linux | golang-bin RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-bin almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-bin almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-bin ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-bin ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang-docs RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-docs almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-docs almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-docs ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-docs ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang-github-openprinting-ipp-usb RHEL 10 | 0.9.27-6.el10_2 | [RHSA-2026:19049](https://patchblox.com/security/data/fix/linux/rhsa-2026-19049.md) | Mar 6, 2026 |
| Linux | golang-misc RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-misc almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-misc almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-misc ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-misc ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang-race RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-race almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-race almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-race ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-race ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang-src RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-src almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-src almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-src ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-src ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | golang-tests RHEL 9 | 0:1.26.2-1.el9_8 | [RHSA-2026:19181](https://patchblox.com/security/data/fix/linux/rhsa-2026-19181.md) | May 27, 2026 |
| Linux | golang-tests almalinux 10 | 1.26.2-2.el10_2.alma.1 | [ALSA-2026:19022](https://patchblox.com/security/data/fix/linux/alsa-2026-19022.md) | May 19, 2026 |
| Linux | golang-tests almalinux 9 | 1.26.2-1.el9_8 | [ALSA-2026:19181](https://patchblox.com/security/data/fix/linux/alsa-2026-19181.md) | May 19, 2026 |
| Linux | golang-tests ol 10 | 0:1.26.2-2.0.1.el10_2 | [ELSA-2026-19022](https://patchblox.com/security/data/fix/linux/elsa-2026-19022.md) | Jul 8, 2026 |
| Linux | golang-tests ol 9 | 0:1.26.2-1.0.1.el9_8 | [ELSA-2026-19181](https://patchblox.com/security/data/fix/linux/elsa-2026-19181.md) | Jun 12, 2026 |
| Linux | govulncheck-vulndb opensuse-leap 15.6 | 0.0.20260317T205859-150000.1.152.1 | [SUSE-SU-2026:1042-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1042-1.md) | Mar 25, 2026 |
| Linux | govulncheck-vulndb opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | [OPENSUSE-SU-2026:21483-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21483-1.md) | Jul 30, 2026 |
| Linux | grafana RHEL 10 | 10.2.6-26.el10_0 | [RHSA-2026:67517](https://patchblox.com/security/data/fix/linux/rhsa-2026-67517.md) | Jul 6, 2026 |
| Linux | grafana-pcp RHEL 10 | 5.3.0-1.el10_0 | [RHSA-2026:56143](https://patchblox.com/security/data/fix/linux/rhsa-2026-56143.md) | Jun 2, 2026 |
| Linux | image-builder RHEL 10 | 52.1-1.el10_2 | [RHSA-2026:22937](https://patchblox.com/security/data/fix/linux/rhsa-2026-22937.md) | Mar 12, 2026 |
| Linux | image-builder RHEL 9 | 0:52.1-1.el9_8 | [RHSA-2026:23228](https://patchblox.com/security/data/fix/linux/rhsa-2026-23228.md) | May 15, 2026 |
| Linux | image-builder ol 10 | 0:58-1.0.1.el10 | [ELSA-2026-22937](https://patchblox.com/security/data/fix/linux/elsa-2026-22937.md) | Jul 16, 2026 |
| Linux | image-builder ol 9 | 0:72.0.0-1.0.1.el9 | [ELSA-2026-23228](https://patchblox.com/security/data/fix/linux/elsa-2026-23228.md) | Sep 3, 2026 |
| Linux | image-builder rocky 10 | 0:52.1-1.el10_2.rocky.0.1 | [RLSA-2026:22937](https://patchblox.com/security/data/fix/linux/rlsa-2026-22937.md) | Jun 5, 2026 |
| Linux | image-builder rocky 9 | 0:52.1-1.el9_8 | [RLSA-2026:23228](https://patchblox.com/security/data/fix/linux/rlsa-2026-23228.md) | Jun 5, 2026 |
| Linux | ipp-usb ol 10 | 0:0.9.27-6.el10_2 | [ELSA-2026-19049](https://patchblox.com/security/data/fix/linux/elsa-2026-19049.md) | Jul 8, 2026 |
| Linux | osbuild-composer RHEL 10 | 165.1-2.el10_2 | [RHSA-2026:22450](https://patchblox.com/security/data/fix/linux/rhsa-2026-22450.md) | Mar 12, 2026 |
| Linux | osbuild-composer RHEL 9 | 0:165.1-2.el9_8 | [RHSA-2026:22714](https://patchblox.com/security/data/fix/linux/rhsa-2026-22714.md) | Jun 24, 2026 |
| Linux | osbuild-composer ol 10 | 0:176-1.0.1.el10_2 | [ELSA-2026-22450](https://patchblox.com/security/data/fix/linux/elsa-2026-22450.md) | Aug 13, 2026 |
| Linux | osbuild-composer ol 9 | 0:175-1.0.1.el9_8 | [ELSA-2026-22714](https://patchblox.com/security/data/fix/linux/elsa-2026-22714.md) | Aug 5, 2026 |
| Linux | osbuild-composer rocky 10 | 0:165.1-2.el10_2.rocky.0.1 | [RLSA-2026:22450](https://patchblox.com/security/data/fix/linux/rlsa-2026-22450.md) | Jun 5, 2026 |
| Linux | osbuild-composer rocky 9 | 0:165.1-2.el9_8.rocky.0.1 | [RLSA-2026:22714](https://patchblox.com/security/data/fix/linux/rlsa-2026-22714.md) | Jun 11, 2026 |
| Linux | osbuild-composer-core RHEL 9 | 0:165.1-2.el9_8 | [RHSA-2026:22714](https://patchblox.com/security/data/fix/linux/rhsa-2026-22714.md) | Jun 24, 2026 |
| Linux | osbuild-composer-core ol 10 | 0:176-1.0.1.el10_2 | [ELSA-2026-22450](https://patchblox.com/security/data/fix/linux/elsa-2026-22450.md) | Aug 13, 2026 |
| Linux | osbuild-composer-core ol 9 | 0:175-1.0.1.el9_8 | [ELSA-2026-22714](https://patchblox.com/security/data/fix/linux/elsa-2026-22714.md) | Aug 5, 2026 |
| Linux | osbuild-composer-worker RHEL 9 | 0:165.1-2.el9_8 | [RHSA-2026:22714](https://patchblox.com/security/data/fix/linux/rhsa-2026-22714.md) | Jun 24, 2026 |
| Linux | osbuild-composer-worker ol 10 | 0:176-1.0.1.el10_2 | [ELSA-2026-22450](https://patchblox.com/security/data/fix/linux/elsa-2026-22450.md) | Aug 13, 2026 |
| Linux | osbuild-composer-worker ol 9 | 0:175-1.0.1.el9_8 | [ELSA-2026-22714](https://patchblox.com/security/data/fix/linux/elsa-2026-22714.md) | Aug 5, 2026 |
| Linux | rhc-worker-playbook RHEL 10 | 0.2.3-4.el10_0 | [RHSA-2026:10929](https://patchblox.com/security/data/fix/linux/rhsa-2026-10929.md) | Mar 6, 2026 |

---

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