CVE-2026-42508
Description
A flaw was found in golang.org/x/crypto/ssh/knownhosts. This vulnerability occurs because the system did not correctly check for the revocation status of a SignatureKey belonging to a Certificate Authority (CA). A remote attacker could potentially exploit this by presenting a revoked key, leading to the system accepting it as valid. This could allow an attacker to bypass security checks and potentially gain unauthorized access or spoof legitimate entities.
Statement
Important: A flaw in golang.org/x/crypto/ssh/knownhosts allows a remote attacker to bypass security checks. This vulnerability arises because the system fails to properly verify the revocation status of a Certificate Authority (CA) SignatureKey. In Red Hat environments, this could enable an attacker to present a revoked key, leading to its acceptance as valid and potentially granting unauthorized access or facilitating the spoofing of legitimate entities.
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 | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Integrity,Authentication
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The product might connect to a malicious host while believing it is a trusted host, or the product might be deceived into accepting spoofed data that appears to originate from a trusted host.
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