SSH host authentication bypass via unchecked CA key
Published May 22, 2026 · Updated Sep 15, 2026
Improper certificate validation in Go x/crypto/ssh/knownhosts before 0.52.0 allows remote attackers to bypass SSH host checks. hostKeyDB.IsRevoked checks the presented certificate key but fails to check its CA SignatureKey against @revoked entries. Exploitation requires a certificate signed by a revoked CA key, allowing a malicious SSH endpoint to be accepted as trusted.
Summary
What happened
Improper certificate validation in Go x/crypto/ssh/knownhosts before 0.52.0 allows remote attackers to bypass SSH host checks. hostKeyDB.IsRevoked checks the presented certificate key but fails to check its CA SignatureKey against @revoked entries. Exploitation requires a certificate signed by a revoked CA key, allowing a malicious SSH endpoint to be accepted as trusted.
The record
- CVE
- CVE-2026-42508
- Published
- May 22, 2026
- Updated
- Sep 15, 2026
- Vendor
- Red Hat
- Product
- cert-manager Operator for Red Hat OpenShift
- Classifications
- CWE-295, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 22, 2026CVE publishedPublication date reported by the CVE source.
- Sep 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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