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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | OpenSSH | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4.13 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4.14 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4.15 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4.16 | — | — |
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | openssh +4 | 8.7p1-38.el9_4.4 | RHSA-2024:4457 |
| RHEL 9 | pam_ssh_agent_auth | 0.10.4-5.38.el9_4.4 | RHSA-2024:4457 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.2 EUS | openssh +4 | 8.7p1-30.el9_2.7 | RHSA-2024:4716 |
| RHEL 9.2 EUS | pam_ssh_agent_auth | 0.10.4-5.30.el9_2.7 | RHSA-2024:4716 |
| RHEL 9.0 E4S | openssh +4 | 8.7p1-12.el9_0.3 | RHSA-2024:4910 |
| RHEL 9.0 E4S | pam_ssh_agent_auth | 0.10.4-4.12.el9_0.3 | RHSA-2024:4910 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | openssh +4 | 8.7p1-38.el9_4.4 | ALSA-2024:4457 |
| AlmaLinux 9 | pam_ssh_agent_auth | 0.10.4-5.38.el9_4.4 | ALSA-2024:4457 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 9 | openssh | 8.7p1-38.el9_4.4 | RLSA-2024:4457 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | openssh +3 | 8.7p1-8.amzn2023.0.12 | ALAS2023-2024-651 |
| Amazon Linux 2023 | pam_ssh_agent_auth | 0.10.4-4.8.amzn2023.0.12 | ALAS2023-2024-651 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | openssh +4 | 8.7p1-38.0.2.el9_4.4 | ELSA-2024-4457 |
| Oracle Linux 9 | pam_ssh_agent_auth | 0.10.4-5.38.0.2.el9_4.4 | ELSA-2024-4457 |
Advisories 11
- ALSA-2024:4457 Moderate: openssh security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2024:4910 Red Hat Security Advisory: openssh security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2024:4716 Red Hat Security Advisory: openssh security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2024:4457 Red Hat Security Advisory: openssh security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- WID-SEC-2024-1913 Red Hat OpenShift Container Platform: Mehrere Schwachstellen BSI CERT-Bund (WID) · Mar 3, 2026
- RLSA-2024:4457 Moderate: openssh security update Rocky Linux Security Advisories · Feb 4, 2026
- WID-SEC-2024-1547 OpenSSH auf Red Hat Enterprise Linux 9: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Oct 29, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- ALAS2023-2024-651 Important: openssh security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Jul 22, 2024
- ELSA-2024-4457 Moderate: openssh security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 10, 2024
References
- RHSA-2024:4457 vendor-advisory
- RHSA-2024:4613 vendor-advisory
- RHSA-2024:4716 vendor-advisory
- RHSA-2024:4910 vendor-advisory
- RHSA-2024:4955 vendor-advisory
- RHSA-2024:4960 vendor-advisory
- RHSA-2024:5444 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2024-6409 vdb-entry
- RHBZ#2295085 issue-tracking