CVE-2024-6409OpenSSH Vulnerability
A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd).
Published Jul 8, 2024 · Updated Oct 21, 2026
Key Facts
Patch immediately- CVE-2024-6409 is a high-severity vulnerability (CVSS 7.0 v3.1) affecting 9 (Enterprise Linux), 4.13 (Openshift), 4.14 (Openshift) and 14 more products.
- It is exploited in the wild, listed in Industry KEV feed since Mar 12, 2025. No public exploit code is known.
- EPSS estimates a 28% probability of exploitation in the next 30 days.
- Fixed versions are available, including OpenSSH 0:8.7p1-12.el9_0.3, OpenSSH 8.7p1-38.0.2.el9_4.4, OpenSSH 8.7p1-38.el9_4.4.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v3.1
7.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
EPSS (30-day exploit likelihood)
28%
Higher than 98.1% of all scored CVEs
Exploit maturity
Exploited (KEV)
ATLAS score
53/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Mar 12, 2025
247 days after publication
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Exploited (KEV)
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Advisories And Exploit References
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2024-6409
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2024-6409
- advisoryRHSA-2024:4457
- advisoryRHSA-2024:4613
- advisoryRHSA-2024:4716
- advisoryRHSA-2024:4910
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Mar 12, 2025 | n/a | Not reported |
Affected Products
41 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| 9Enterprise Linux | See advisory | n/a |
| 4.13Openshift | See advisory | n/a |
| 4.14Openshift | See advisory | n/a |
| 4.15Openshift | See advisory | n/a |
| 4.16Openshift | See advisory | n/a |
Patched Releases
OpenSSH
0:8.7p1-12.el9_0.3, 8.7p1-38.0.2.el9_4.4, 8.7p1-38.el9_4.4, 8.7p1-8.amzn2023.0.12
openssh-askpass
8.7p1-38.0.2.el9_4.4
openssh-clients
8.7p1-38.0.2.el9_4.4, 8.7p1-8.amzn2023.0.12
openssh-keycat
8.7p1-38.0.2.el9_4.4, 8.7p1-8.amzn2023.0.12
openssh-server
8.7p1-38.0.2.el9_4.4, 8.7p1-8.amzn2023.0.12
pam_ssh_agent_auth
0.10.4-4.8.amzn2023.0.12, 0.10.4-5.38.0.2.el9_4.4
rhcos
414.92.202407300859-0
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
V3.1.5
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
V3.1.5
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
V3.1.5
Timeline
Publicly disclosed
Jul 8, 2024
Added to Industry KEV feed
Mar 12, 2025
Last updated
Oct 21, 2026
Weakness Type
- CWE-364 Signal Handler Race Condition
References
- advisorycve.org · CVERecord
- advisorynvd.nist.gov · CVE-2024-6409
- advisoryRHSA-2024:4457
- advisoryRHSA-2024:4613
- advisoryRHSA-2024:4716
FAQ
Common Questions.
A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd).
Affected: 9 (Enterprise Linux); 4.13 (Openshift); 4.14 (Openshift), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Mar 12, 2025.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including OpenSSH 0:8.7p1-12.el9_0.3, OpenSSH 8.7p1-38.0.2.el9_4.4, OpenSSH 8.7p1-38.el9_4.4.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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