CVE-2026-27137
Incorrect enforcement of email constraints in crypto/x509
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.
INFO
Published Date :
March 6, 2026, 10:16 p.m.
Last Modified :
April 21, 2026, 2:40 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update certificate validation logic.
- Ensure all email constraints are processed.
- Test with diverse email constraint scenarios.
Public PoC/Exploit Available at Github
CVE-2026-27137 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27137.
| URL | Resource |
|---|---|
| https://go.dev/cl/752182 | Mailing List |
| https://go.dev/issue/77952 | Issue Tracking |
| https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk | Release Notes |
| https://pkg.go.dev/vuln/GO-2026-4599 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27137 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27137
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Deterministic CVE assessment tool for medik8s operators
Dockerfile Go Makefile Shell
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27137 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27137 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 21, 2026
Action Type Old Value New Value Added CWE CWE-295 Added CPE Configuration OR *cpe:2.3:a:golang:go:1.26.0:*:*:*:*:*:*:* Added Reference Type Go Project: https://go.dev/cl/752182 Types: Mailing List Added Reference Type Go Project: https://go.dev/issue/77952 Types: Issue Tracking Added Reference Type Go Project: https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk Types: Release Notes Added Reference Type Go Project: https://pkg.go.dev/vuln/GO-2026-4599 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by [email protected]
Mar. 06, 2026
Action Type Old Value New Value Added 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. Added Reference https://go.dev/cl/752182 Added Reference https://go.dev/issue/77952 Added Reference https://groups.google.com/g/golang-announce/c/EdhZqrQ98hk Added Reference https://pkg.go.dev/vuln/GO-2026-4599