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Fencer Vulns
high 7.0

CVE-2024-6409 in the critical feed json

Openssh: possible remote code execution due to a race condition in signal handling affecting red hat enterprise linux 9

published 2024-07-08 2 y ago modified 2026-11-06 2 d ago also EUVD-2024-47983

cvss
7.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
27.9%
EPSS 27.9% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

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 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.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 9 0:8.7p1-38.el9_4.4
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions 0:8.7p1-12.el9_0.3
  • Red Hat Red Hat Enterprise Linux 9.2 Extended Update Support 0:8.7p1-30.el9_2.7
  • Red Hat Red Hat OpenShift Container Platform 4.13 413.92.202408122222-0
  • Red Hat Red Hat OpenShift Container Platform 4.14 414.92.202407300859-0
  • Red Hat Red Hat OpenShift Container Platform 4.15 415.92.202407301159-0
  • Red Hat Red Hat OpenShift Container Platform 4.16 416.94.202407171205-0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • openssh RHEL 9 8.7p1-38.el9_4.4
  • openssh-keycat RHEL 9 8.7p1-38.el9_4.4
  • openssh-server RHEL 9 8.7p1-38.el9_4.4
  • openssh-askpass RHEL 9 8.7p1-38.el9_4.4
  • openssh-clients RHEL 9 8.7p1-38.el9_4.4
  • pam_ssh_agent_auth RHEL 9 0.10.4-5.38.el9_4.4
  • openssh RHEL 9.0 E4S 8.7p1-12.el9_0.3
  • openssh-keycat RHEL 9.0 E4S 8.7p1-12.el9_0.3

red hat advisories RHSA-2024:4910RHSA-2024:4716RHSA-2024:4457

  • openssh AlmaLinux 9 8.7p1-38.el9_4.4
  • openssh-keycat AlmaLinux 9 8.7p1-38.el9_4.4
  • openssh-server AlmaLinux 9 8.7p1-38.el9_4.4
  • openssh-askpass AlmaLinux 9 8.7p1-38.el9_4.4
  • openssh-clients AlmaLinux 9 8.7p1-38.el9_4.4
  • pam_ssh_agent_auth AlmaLinux 9 0.10.4-5.38.el9_4.4

almalinux advisories ALSA-2024:4457

  • openssh Rocky Linux 9 8.7p1-38.el9_4.4

rocky linux advisories RLSA-2024:4457

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-6409 updated cvss 7.0

openssh: Possible remote code execution due to a race condition in signal handling affecting Red Hat Enterprise Linux 9

  • Red Hat Enterprise Linux AppStream (v. 9) openssh-askpass 8.7p1-38.el9_4.4, pam_ssh_agent_auth 0.10.4-5.38.el9_4.4
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4457
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) openssh-askpass 8.7p1-12.el9_0.3, pam_ssh_agent_auth 0.10.4-4.12.el9_0.3
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4910
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) openssh-askpass 8.7p1-30.el9_2.7, pam_ssh_agent_auth 0.10.4-5.30.el9_2.7
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4716
  • Red Hat Enterprise Linux BaseOS (v. 9) openssh 8.7p1-38.el9_4.4, openssh-keycat 8.7p1-38.el9_4.4, openssh-server 8.7p1-38.el9_4.4, openssh-clients 8.7p1-38.el9_4.4
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4457
  • Red Hat Enterprise Linux BaseOS E4S (v.9.0) openssh 8.7p1-12.el9_0.3, openssh-keycat 8.7p1-12.el9_0.3, openssh-server 8.7p1-12.el9_0.3, openssh-clients 8.7p1-12.el9_0.3
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4910
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) openssh 8.7p1-30.el9_2.7, openssh-keycat 8.7p1-30.el9_2.7, openssh-server 8.7p1-30.el9_2.7, openssh-clients 8.7p1-30.el9_2.7
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4716
  • Red Hat OpenShift Container Platform 4.13 rhcos 413.92.202408122222-0
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:5444
  • Red Hat OpenShift Container Platform 4.14 rhcos 414.92.202407300859-0
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4960
show 3 more
  • Red Hat OpenShift Container Platform 4.15 rhcos 415.92.202407301159-0
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4955
  • Red Hat OpenShift Container Platform 4.16 rhcos 416.94.202407171205-0
    fixed: vendor fix “The process is identical to CVE-2024-6387, by disabling LoginGraceTime. See that CVE page for additional details.” RHSA-2024:4613
  • Red Hat Enterprise Linux 6 openssh, openssh-ldap, openssh-server, openssh-askpass, openssh-clients, pam_ssh_agent_auth Red Hat Enterprise Linux 7 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +3 more Red Hat Enterprise Linux 8 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +2 more Red Hat Enterprise Linux 10 openssh Red Hat OpenShift Container Platform 4.13 openshift4/ose-cli v4.13.0-202408131940.p0.gd192e90.assembly.stream.el8, openshift4/ose-pod v4.13.0-202408131940.p0.ge0953cc.assembly.stream.el8, openshift4/ose-tests v4.13.0-202408131940.p0.gaedd6b8.assembly.stream.el8, openshift4/ose-console v4.13.0-202408131940.p0.g62a2dbc.assembly.stream.el8, openshift4/ose-coredns v4.13.0-202408131940.p0.g298d919.assembly.stream.el8, openshift4/ose-deployer v4.13.0-202408131940.p0.gd192e90.assembly.stream.el8, +186 more Red Hat OpenShift Container Platform 4.14 openshift4/ose-cli v4.14.0-202407260844.p0.g44b3ac2.assembly.stream.el8, openshift4/ose-tests v4.14.0-202407260844.p0.g3a80e94.assembly.stream.el8, openshift4/ose-console v4.14.0-202407310940.p0.geb981dc.assembly.stream.el8, openshift4/ose-deployer v4.14.0-202407260844.p0.g44b3ac2.assembly.stream.el8, openshift4/ose-installer v4.14.0-202407301039.p0.g0363a65.assembly.stream.el8, openshift4/ose-sdn-rhel8 v4.14.0-202407260844.p0.g1a9befc.assembly.stream.el8, +36 more
    +2 more products
    Red Hat OpenShift Container Platform 4.15 openshift4/ose-tests v4.15.0-202407292139.p0.gf3e8dee.assembly.stream.el8, openshift4/ose-console v4.15.0-202407311708.p0.ge8514d6.assembly.stream.el8, openshift4/ose-installer v4.15.0-202407290438.p0.g11bd060.assembly.stream.el8, openshift4/ose-sdn-rhel9 v4.15.0-202407250107.p0.g71a6f28.assembly.stream.el9, openshift4/ose-ironic-rhel9 v4.15.0-202407261238.p0.g6f6b05a.assembly.stream.el9, openshift4/network-tools-rhel8 v4.15.0-202407301737.p0.g17536c8.assembly.stream.el8, +28 more Red Hat OpenShift Container Platform 4.16 openshift4/ose-cli-rhel9 v4.16.0-202407111006.p0.gfa84651.assembly.stream.el9, openshift4/ose-sdn-rhel9 v4.16.0-202407111006.p0.g5b658c4.assembly.stream.el9, openshift4/ose-tests-rhel9 v4.16.0-202407151406.p0.gac6867d.assembly.stream.el9, openshift4/ose-tools-rhel9 v4.16.0-202407150636.p0.gfa84651.assembly.stream.el9, openshift4/ose-ironic-rhel9 v4.16.0-202407150135.p0.g39aee9b.assembly.stream.el9, openshift4/ose-console-rhel9 v4.16.0-202407181806.p0.g897c0f7.assembly.stream.el9, +38 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-23-348-10 updated cvss 7.0

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

27.93% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

Affected products

  • 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
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-364 Signal Handler Race Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.