CVE-2024-6409

HIGH
Published Jul 8, 2024 Modified Apr 15, 2026 CWE-364

Description

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.

CVSS v3.1 Score

7.0
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

Weakness Type (CWE)

CWE-364 CWE-364

References

Frequently Asked Questions

What is CVE-2024-6409? +
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. It has a CVSS v3.1 base score of 7.0 (HIGH).
How severe is CVE-2024-6409? +
CVE-2024-6409 has a CVSS v3.1 score of 7.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
How do I check if I'm vulnerable to CVE-2024-6409? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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