CVE-2026-33810
Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509
8.2
HIGH
CVSS 3.1
EPSS 0.01%
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.
How to fix CVE-2026-33810
To remediate CVE-2026-33810, upgrade the affected package to a fixed version below.
- —upgrade to 1.26.2 or later
- —upgrade to 1.26.2-1 or later
- —upgrade to 1.26.2 or later
Is CVE-2026-33810 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- >= 1.26.0-0, < 1.26.2
- from 0, < 1.26.2-1
- >= 1.26.0-0, < 1.26.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N |