CVE-2026-39835
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk42th percentile - higher than 42% of all known CVEs
Summary
SSH servers using CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority can panic when a client presents a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil.
Risk Assessment
An attacker can cause the SSH server to panic, leading to denial of service (DoS).
Recommendation
Update the CertChecker library to a version that fixes this behavior, or set the appropriate IsUserAuthority and IsHostAuthority callbacks.
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Original NVD description (English source)
SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

