{"id":"CVE-2024-6409","title":"A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd)","summary":"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…","severity":"high","cvss":7,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","cwe":["CWE-364"],"published":"2024-07-08","updated":"2026-08-21","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2024-6409","references":[{"url":"https://access.redhat.com/errata/RHSA-2024:4457","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:4613","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:4716","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:4910","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:4955","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:4960","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:5444","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2024-6409","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2295085","label":"secalert@redhat.com"},{"url":"http://www.openwall.com/lists/oss-security/2024/07/08/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2024/07/09/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2024/07/09/5","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2024/07/10/1","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2024/07/10/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2024:4457","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2024:4613","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2024:4716","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/security/cve/CVE-2024-6409","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://almalinux.org/blog/2024-07-09-cve-2024-6409/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2295085","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.suse.com/show_bug.cgi?id=1227217","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://explore.alas.aws.amazon.com/CVE-2024-6409.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/openela-main/openssh/commit/c00da7741d42029e49047dd89e266d91dcfbffa0","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security-tracker.debian.org/tracker/CVE-2024-6409","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20240712-0003/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://sig-security.rocky.page/issues/CVE-2024-6409/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ubuntu.com/security/CVE-2024-6409","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.suse.com/security/cve/CVE-2024-6409.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.27935,"epssPercentile":0.98063,"ingestedAt":"2026-08-21T13:17:17.636Z","slug":"CVE-2024-6409","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":44,"depthScoreParts":{"impact":38.5,"likelihood":5.6,"exploitation":0,"ransomware":0},"changes":[]}