CVE-2024-6409

The record

A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd). If a remote attacker does not authenticate within a set time period, then sshd's SIGALRM handler is called asynchronously. However, this signal handler calls various functions that are not async-signal-safe, for example, syslog(). As a consequence of a successful attack, in the worst case scenario, an attacker may be able to perform a remote code execution (RCE) as an unprivileged user running the sshd server.

Affected packages

Related vulnerabilities

• CVE-2024-6387 A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). Also affects openssh
• CVE-2023-51385 In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host… Also affects openssh
• CVE-2023-48795 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… Also affects openssh
• CVE-2023-25136 OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during… Also affects openssh
• CVE-2026-42002 Concurrency and locking defects in GSS-TSIG CWE-364
• CVE-2026-33565 in OpenHarmony v6.0 and prior versions allow a local attacker cause DOS. CWE-364
• CVE-2026-27766 in OpenHarmony v6.0 and prior versions allow a local attacker cause information leak. CWE-364
• CVE-2026-24792 in OpenHarmony v6.0 and prior versions allow a remote attacker arbitrary code execution… CWE-364