5.9

CVE-2026-27138: Panic in name constraint checking for malformed certificates in crypto/x509

Analyzed
AliasesUBUNTU-CVE-2026-27138DEBIAN-CVE-2026-27138CGA-2474-pxpq-p85w
Published 06-03-2026Last modified 10-03-2026

Vulnerability summary

CVE-2026-27138 is a medium (CVSS 5.9) Improper Certificate Validation vulnerability in go standard library crypto/x509. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 32.2% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.38%
0%100%
Low · +0.05 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 12 · Related 12
MGASA-2026-0147OPENSUSE-SU-2026:10299-1OPENSUSE-SU-2026:10509-1OPENSUSE-SU-2026:20342-1OPENSUSE-SU-2026:20537-1OPENSUSE-SU-2026:21483-1

Timeline

  1. 06-03-2026
    PublishedVulnerability first disclosed.
  2. 10-03-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.38%

Chance of exploitation in the next 30 days

Percentile

32%

Versus all other CVEs

30-day change

Increase +0.05 pp

From 0.33% 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

8 vendors · 144 products

References

12 links
Show all 12 references