CVE-2026-33810

HIGH

Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509

Title source: cna
STIX 2.1

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.

References (52)

Core 52
Core References

Scores

CVSS v3 8.2
EPSS 0.0034
EPSS Percentile 26.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-1289 CWE-295
Status published
Products (2)
Go standard library/crypto/x509 1.26.0-0 - 1.26.2
golang/go 1.26.0 - 1.26.2
Published Apr 08, 2026
Tracked Since Apr 08, 2026