7.5

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

Modified
AliasesUBUNTU-CVE-2026-27137DEBIAN-CVE-2026-27137CGA-226c-637x-r3cc
Published 06-03-2026Last modified 18-09-2026

Vulnerability summary

CVE-2026-27137 is a high (CVSS 7.5) Improper Certificate Validation vulnerability in go standard library crypto/x509. EPSS estimates a 0.66% chance of exploitation in the next 30 days, higher than 51.6% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.66%
0%100%
Low · -0.03 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 41 · Related 41
MGASA-2026-0147OPENSUSE-SU-2026:10299-1OPENSUSE-SU-2026:20342-1OPENSUSE-SU-2026:20537-1OPENSUSE-SU-2026:21483-1RHSA-2026:10169

Timeline

  1. 06-03-2026
    PublishedVulnerability first disclosed.
  2. 18-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.66%

Chance of exploitation in the next 30 days

Percentile

52%

Versus all other CVEs

30-day change

Decrease -0.03 pp

From 0.69% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard98 products
  • amazon-k8s-cni-fips< 1.21.1-r6
  • amazon-k8s-cni-init-fips< 1.21.1-r6
  • amazon-k8s-cni-init-fips-compat< 1.21.1-r6
  • aws-ebs-csi-driver-1.56< 1.56.0-r3
  • aws-ebs-csi-driver-fips-1.56< 1.56.0-r3
Wolfi37 products
  • dkron< 4.1.0-r2
  • dkron-executor-gcppubsub< 4.1.0-r2
  • dkron-executor-grpc< 4.1.0-r2
  • dkron-executor-kafka< 4.1.0-r2
  • dkron-executor-nats< 4.1.0-r2
Ubuntu3 products
  • golang-1.24All versions (No fix recorded)
  • golang-1.25All versions (No fix recorded)
  • golang-1.26All versions (No fix recorded)
Alpine2 products
  • go< 1.25.8-r0
  • rclone< 1.73.5-r0
Debian1 product
  • golang-1.26< 1.26.1-1
Go1 product
  • stdlib≥ 1.26.0-0, < 1.26.1
Go standard library1 product
Golang1 product
Opensuse1 product
  • kubelogin&distro=openSUSE Tumbleweed< 0.2.18-1.1

9 vendors · 145 products

References

76 links
Show all 76 references