CVE-2026-33810
Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509
Description
When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool.
INFO
Published Date :
April 8, 2026, 2:16 a.m.
Last Modified :
April 8, 2026, 2:16 a.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-33810
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Apply the latest security update for certificate validation.
- Ensure certificate validation logic handles case-insensitive DNS SANs.
- Configure certificate validation to enforce DNS constraints strictly.
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-2026-33810.
| URL | Resource |
|---|---|
| https://go.dev/cl/763763 | |
| https://go.dev/issue/78332 | |
| https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU | |
| https://pkg.go.dev/vuln/GO-2026-4866 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33810 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-2026-33810
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).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33810 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33810 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.
-
New CVE Received by [email protected]
Apr. 08, 2026
Action Type Old Value New Value Added Description When verifying a certificate chain containing excluded DNS constraints, these constraints are not correctly applied to wildcard DNS SANs which use a different case than the constraint. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool. Added Reference https://go.dev/cl/763763 Added Reference https://go.dev/issue/78332 Added Reference https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU Added Reference https://pkg.go.dev/vuln/GO-2026-4866