CVE-2026-33810
HIGH8.2EPSS 0.01%Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509
Published: 4/7/2026Modified: 5/21/2026
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.
Affected packages (3)
- Bitnami/golang>= 1.26.0-0, < 1.26.2
- Debian/golang-1.26from 0, < 1.26.2-1
- Go/stdlib>= 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 |
References (8)
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-33810
- PATCHhttps://go.dev/cl/763763
- REPORThttps://go.dev/issue/78332
- WEBhttps://groups.google.com/g/golang-announce/c/0uYbvbPZRWU
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2026-33810
- WEBhttps://pkg.go.dev/vuln/GO-2026-4866
- WEBhttp://www.openwall.com/lists/oss-security/2026/04/19/4
- WEBhttp://www.openwall.com/lists/oss-security/2026/04/20/1