CVE-2024-6409

HIGH
MEDIUM Priority: 1.96 BB Relevance: 70/100
Published: 2024-07-08 Modified: 2026-11-06 First seen: 2026-11-03 Status: active

Attack Surface

Network No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: High
PR: None
UI: None
S: Unchanged
C: Low
I: Low
A: High

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.

References & Advisories (24)

https://access.redhat.com/errata/RHSA-2024:4457
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:4613
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:4716
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:4910
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:4955
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:4960
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2024:5444
vendor-advisory x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2295085
issue-tracking x_refsource_REDHAT

Bug Bounty Relevance

70 / 100
✓ Network accessible
✓ No authentication
✓ No user interaction

CVSS Score

7.0 / 10.0 v3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

EPSS — Exploitation Probability

27.93%
Raw Score 0.279350
Percentile 98.1%
Date 2026-11-08

EPSS Trend

2026-11-08
0.27935
2026-11-07
0.27935
2026-11-06
0.27935
2026-11-05
0.27935
2026-11-04
0.27935
2026-11-03
0.27935

Intelligence Sources

mitre ref →
nvd ref →