CVE-2026-33810 | Case-sensitive excludedSubtrees name constraints cause Auth Bypass in crypto/x509

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.

Published: 2026-04-08 Last update: 2026-04-20 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33810 is rated Low Risk (32.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33810

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-08 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33810

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.2 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-33810

GitHub Security Advisory for CVE-2026-33810

GHSA-fv83-x2xw-2j55 · Severity: high — When verifying a certificate chain containing excluded DNS constraints, these constraints are not...

OS Trackers for CVE-2026-33810

vendor priority summary link
alpine — CVE-2026-33810: 1 source package rows (go); 7 state rows across 2 repos (3.23-community, edge-community); fixed 2, open 5. https://security.alpinelinux.org/vuln/CVE-2026-33810
debian unimportant CVE-2026-33810 unimportant priority: Debian including 5 source packages (golang-1.15, golang-1.19, golang-1.24, golang-1.25, golang-1.26), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 7. https://security-tracker.debian.org/tracker/CVE-2026-33810
redhat high — https://access.redhat.com/security/cve/CVE-2026-33810
suse medium CVE-2026-33810 severity moderate: SUSE including 16 source package names (go, go-doc, …), 134 product×package rows across 16 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (16 product lines)): Known Not Affected 94, Fixed 40. https://www.suse.com/security/cve/CVE-2026-33810/
ubuntu medium CVE-2026-33810 medium priority: Ubuntu including 16 source packages (golang, golang-1.10, …), 82 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): needs-triage 49, DNE 33. https://ubuntu.com/security/CVE-2026-33810

Affected software / configurations for CVE-2026-33810

Vendor Product Version Raw CPE
golang go >= 1.26.0, < 1.26.2 cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*

References for CVE-2026-33810

cvelogic Threat Intelligence