regreSSHion OpenSSH Flaw Exposes sshd to Unauthenticated Remote Code Execution

A high-severity vulnerability tracked as CVE-2024-6387 has been disclosed in OpenSSH sshd, where a race condition in signal handling can let a remote, unauthenticated attacker trigger remote code execution or cause a denial of service by precisely timing a timeout during authentication. The bug, widely referred to as regreSSHion, affects OpenSSH versions 8.5p1 through 9.7p1 and revives a class of weakness in one of the most widely deployed remote administration services on Linux and Unix-like systems.

Reports said the exposure could affect roughly 700,000 Linux systems, underscoring the internet-facing risk for organizations that rely on SSH for remote access. OpenSSH 9.8 and later include a fix, and vendors including Red Hat have issued advisories for impacted deployments, prompting defenders to identify exposed sshd instances, prioritize patching, and review compensating controls for externally reachable SSH services.