CVE-2026-33810
Description
A flaw was found in the crypto/x509 package within Go (golang). When verifying a certificate chain, excluded DNS (Domain Name System) constraints are not correctly applied to wildcard DNS Subject Alternative Names (SANs) if the case of the SAN differs from the constraint. This oversight could allow an attacker to bypass certificate validation, potentially leading to the acceptance of a malicious certificate that should have been rejected. This issue specifically impacts the validation of trusted certificate chains.
Statement
This is an Important flaw in the Go crypto/x509 package that could allow an attacker to bypass certificate validation. The vulnerability arises from an incorrect application of excluded DNS constraints to wildcard DNS Subject Alternative Names (SANs) when their case differs from the constraint. This could lead to Red Hat products accepting malicious certificates from otherwise trusted chains, compromising the trust model.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | 8.2 | 8.8 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | Required | None | Required |
| Scope | Changed | Unchanged | Changed |
| Confidentiality | High | High | High |
| Integrity Impact | Low | Low | Low |
| Availability Impact | Low | None | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:L
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
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