CVE-2024-6387
Openssh: regresshion - race condition in ssh allows rce/dos
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Description
A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate within a set time period.
Official description from the CVE record, published by redhat. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.1 High 8.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: High
The attack depends on conditions outside the attacker's control, so it takes preparation.
Privileges required: None
No account or privileges are needed.
User interaction: None
No action from any user is needed.
Scope: Unchanged
The impact stays within the vulnerable component.
Confidentiality impact: High
Serious or total effect on the secrecy of data.
Integrity impact: High
Serious or total effect on the trustworthiness of data.
Availability impact: High
Serious or total effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity | High | The attack depends on conditions outside the attacker's control, so it takes preparation. |
| Privileges required | None | No account or privileges are needed. |
| User interaction | None | No action from any user is needed. |
| Scope | Unchanged | The impact stays within the vulnerable component. |
| Confidentiality impact | High | Serious or total effect on the secrecy of data. |
| Integrity impact | High | Serious or total effect on the trustworthiness of data. |
| Availability impact | High | Serious or total effect on availability. |
CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.
EPSS
- Score
- 0.99506 (99.5% probability)
- Percentile
- 99.9%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
CISA assessment as of Jul 2, 2024
- Exploitation
- Public proof of concept recorded by CISA
- Automatable
- no
- Technical impact
- total
Weakness (CWE)
- CWE-364Signal Handler Race Condition
Affected products
OpenSSH
- affected: 8.5p1 up to 9.7p1
Red Hat Enterprise Linux 9
- unaffected: 0:8.7p1-38.el9_4.1 up to before *
Red Hat Enterprise Linux 9
- unaffected: 0:8.7p1-38.el9_4.1 up to before *
Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
- unaffected: 0:8.7p1-12.el9_0.1 up to before *
Red Hat Enterprise Linux 9.2 Extended Update Support
- unaffected: 0:8.7p1-30.el9_2.4 up to before *
Red Hat OpenShift Container Platform 4.13
- unaffected: 413.92.202407091321-0 up to before *
Red Hat OpenShift Container Platform 4.14
- unaffected: 414.92.202407091253-0 up to before *
Red Hat OpenShift Container Platform 4.15
- unaffected: 415.92.202407091355-0 up to before *
Red Hat OpenShift Container Platform 4.16
- unaffected: 416.94.202407081958-0 up to before *
Red Hat OpenShift Container Platform 4
Listed as not affected
- Red Hat Ceph Storage 5
- Red Hat Ceph Storage 6
- Red Hat Ceph Storage 7
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
References
- RHSA-2024:4312 (access.redhat.com)vendor-advisory
- RHSA-2024:4340 (access.redhat.com)vendor-advisory
- RHSA-2024:4389 (access.redhat.com)vendor-advisory
- RHSA-2024:4469 (access.redhat.com)vendor-advisory
- RHSA-2024:4474 (access.redhat.com)vendor-advisory
- RHSA-2024:4479 (access.redhat.com)vendor-advisory
- RHSA-2024:4484 (access.redhat.com)vendor-advisory
- access.redhat.com/security/cve/CVE-2024-6387vdb-entry
- RHBZ#2294604 (bugzilla.redhat.com)issue-tracking
- santandersecurityresearch.github.io/blog/sshing_the_masses.…
- openssh.com/txt/release-9.8
- qualys.com/2024/07/01/cve-2024-6387/regresshion.txt
- vicarius.io/vsociety/posts/regresshion-an-openssh-regressio…
- exploit-db.com/exploits/52269
- packetstorm.news/files/id/190587
- openwall.com/lists/oss-security/2024/07/01/12
- openwall.com/lists/oss-security/2024/07/01/13
- openwall.com/lists/oss-security/2024/07/02/1
- openwall.com/lists/oss-security/2024/07/03/1
- openwall.com/lists/oss-security/2024/07/03/11
- openwall.com/lists/oss-security/2024/07/03/2
- openwall.com/lists/oss-security/2024/07/03/3
- openwall.com/lists/oss-security/2024/07/03/4
- openwall.com/lists/oss-security/2024/07/03/5
- openwall.com/lists/oss-security/2024/07/04/1
- openwall.com/lists/oss-security/2024/07/04/2
- openwall.com/lists/oss-security/2024/07/08/2
- openwall.com/lists/oss-security/2024/07/08/3
- openwall.com/lists/oss-security/2024/07/09/2
- openwall.com/lists/oss-security/2024/07/09/5
- openwall.com/lists/oss-security/2024/07/10/1
- openwall.com/lists/oss-security/2024/07/10/2
- openwall.com/lists/oss-security/2024/07/10/3
- openwall.com/lists/oss-security/2024/07/10/4
- openwall.com/lists/oss-security/2024/07/10/6
- openwall.com/lists/oss-security/2024/07/11/1
- openwall.com/lists/oss-security/2024/07/11/3
- openwall.com/lists/oss-security/2024/07/23/4
- openwall.com/lists/oss-security/2024/07/23/6
- openwall.com/lists/oss-security/2024/07/28/2
- openwall.com/lists/oss-security/2024/07/28/3
- archlinux.org/news/the-sshd-service-needs-to-be-restarted-a…
- arstechnica.com/security/2024/07/regresshion-vulnerability-…
- blog.qualys.com/vulnerabilities-threat-research/2024/07/01/…
- explore.alas.aws.amazon.com/CVE-2024-6387.html
- forum.vmssoftware.com/viewtopic.php?f=8&t=9132
- ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2024…
- github.com/AlmaLinux/updates/issues/629
- github.com/Azure/AKS/issues/4379
- github.com/PowerShell/Win32-OpenSSH/discussions/2248
- github.com/PowerShell/Win32-OpenSSH/issues/2249
- github.com/microsoft/azurelinux/issues/9555
- github.com/openela-main/openssh/commit/e1f438970e5a337a1707…
- github.com/oracle/oracle-linux/issues/149
- github.com/rapier1/hpn-ssh/issues/87
- github.com/zgzhang/cve-2024-6387-poc
- lists.almalinux.org/archives/list/[email protected].…
- lists.mindrot.org/pipermail/openssh-unix-announce/2024-July…
- lists.mindrot.org/pipermail/openssh-unix-dev/2024-July/0414…
- news.ycombinator.com/item?id=40843778
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0010
- security-tracker.debian.org/tracker/CVE-2024-6387
- security.netapp.com/advisory/ntap-20240701-0001
- sig-security.rocky.page/issues/CVE-2024-6387
- stackdiary.com/openssh-race-condition-in-sshd-allows-remote…
- ubuntu.com/security/CVE-2024-6387
- ubuntu.com/security/notices/USN-6859-1
- akamai.com/blog/security-research/2024-openssh-vulnerabilit…
- arista.com/en/support/advisories-notices/security-advisory/…
- freebsd.org/security/advisories/FreeBSD-SA-24:04.openssh.asc
- splunk.com/en_us/blog/security/cve-2024-6387-regresshion-vu…
- suse.com/security/cve/CVE-2024-6387.html
- theregister.com/2024/07/01/regresshion_openssh
- support.apple.com/kb/HT214119
- support.apple.com/kb/HT214118
- support.apple.com/kb/HT214120
- seclists.org/fulldisclosure/2024/Jul/20
- seclists.org/fulldisclosure/2024/Jul/18
- seclists.org/fulldisclosure/2024/Jul/19
Timeline
- ID reserved
- Record published
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:52 UTC. Sources and licenses