CVE-2026-27137 | 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.

Published: 2026-03-06 Last update: 2026-04-21 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-27137 is rated Low Risk (30.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-27137

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-07 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-27137

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-27137

GitHub Security Advisory for CVE-2026-27137

GHSA-7hfw-r8qc-89v4 · Severity: high — When verifying a certificate chain which contains a certificate containing multiple email address...

OS Trackers for CVE-2026-27137

vendor priority summary link
alpine — CVE-2026-27137: 1 source package rows (go); 3 state rows across 2 repos (3.23-community, edge-community); fixed 3, open 0. https://security.alpinelinux.org/vuln/CVE-2026-27137
debian unimportant CVE-2026-27137 unimportant priority: Debian including 5 source packages (golang-1.15, golang-1.19, golang-1.24, golang-1.25, golang-1.26), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 7. https://security-tracker.debian.org/tracker/CVE-2026-27137
redhat high — https://access.redhat.com/security/cve/CVE-2026-27137
suse medium — https://www.suse.com/security/cve/CVE-2026-27137/
ubuntu medium CVE-2026-27137 medium priority: Ubuntu including 3 source packages (golang-1.24, golang-1.25, golang-1.26), 12 status rows across 4 suites (jammy, noble, questing, upstream): DNE 5, needs-triage 4, not-affected 2, released 1. https://ubuntu.com/security/CVE-2026-27137

Affected software / configurations for CVE-2026-27137

Vendor Product Version Raw CPE
golang go 1.26.0 cpe:2.3:a:golang:go:1.26.0:*:*:*:*:*:*:*

References for CVE-2026-27137

cvelogic Threat Intelligence