High
Logic error exploit reference
CVE-2024-6387 — Openssh: regresshion - race condition in ssh allows rce/dos
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.
34
Moderate
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Public exploit/PoC (exploitdb)+8
- EPSS 99.5% (30-day exploitation probability)+15
- Technical severity (high)+6
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
99.51%
ahead of 100% of scored CVEs · Oct 15, 2026
Affects
Almalinux
Almalinux and 60 more
CVSS base
8.1
High · 4 source(s)
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — www.openwall.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — lists.mindrot.org (NIST National Vulnerability Database)
- Documented patch — news.ycombinator.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Almalinux Almalinux, Amazon Amazon Linux, Apple Macos…).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Almalinux | Almalinux | version 9.0 | Vulnerable | NIST National Vulnerability Database |
| Amazon | Amazon Linux | version 2023.0 | Vulnerable | NIST National Vulnerability Database |
| Apple | Macos | ≥ 12.0 and < 12.7.6≥ 13.0 and < 13.6.8≥ 14.0 and < 14.6 | Vulnerable | NIST National Vulnerability Database |
| Arista | Eos | ≥ 4.32.0 and ≤ 4.32.1f | Vulnerable | NIST National Vulnerability Database |
| Canonical | Ubuntu Linux | version 23.10version 24.04version 22.04version 22.10version 23.04 | Vulnerable | NIST National Vulnerability Database |
| Debian | Debian Linux | version 12.0 | Vulnerable | NIST National Vulnerability Database |
| Freebsd | Freebsd |
version 13.2-p10version 13.2-p11version 13.2-p2version 13.2-p3version 13.2-p1version 13.2-p4version 13.2-p5version 13.2-p6 and 21 moreversion 13.2-p7version 13.2-p8version 13.2version 13.2-p9version 13.3version 13.3-p1version 13.3-p2version 14.0version 13.3-p3version 14.1-p1version 14.1version 14.0-rc4-p1version 14.0-rc3version 14.0-p7version 14.0-p6version 14.0-p5version 14.0-p4version 14.0-p3version 14.0-p2version 14.0-p1version 14.0-beta5 |
Vulnerable | NIST National Vulnerability Database |
| Netapp | 500f Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | 8300 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | 8700 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A150 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A1k Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A220 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A250 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A400 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A70 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A700s Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A800 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A90 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A900 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | A9500 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Active Iq Unified Manager | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Bootstrap Os | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | C190 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | C250 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | C400 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | C800 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | E-series Santricity Os Controller | ≥ 11.0.0 and ≤ 11.70.2 | Vulnerable | NIST National Vulnerability Database |
| Netapp | Fas2720 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Fas2750 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Fas2820 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Ontap | version 9 | Vulnerable | NIST National Vulnerability Database |
| Netapp | Ontap Select Deploy Administration Utility | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Ontap Tools | version 10version 9 | Vulnerable | NIST National Vulnerability Database |
| Netbsd | Netbsd | ≤ 10.0.0 | Vulnerable | NIST National Vulnerability Database |
| Openbsd | Openssh | ≥ 8.6 and ≤ 9.8version 8.6< 4.4version 4.4version 8.5-p1 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux | version 9.0 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Eus | version 9.4 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Arm 64 | version 9.0_aarch64 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Arm 64 Eus | version 9.4_aarch64 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Ibm Z Systems | version 9.0_s390x | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Ibm Z Systems Eus | version 9.4_s390x | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Power Little Endian | version 9.0_ppc64le | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux For Power Little Endian Eus | version 9.4_ppc64le | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Server Aus | version 9.4 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Openshift Container Platform | version 4.0 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Red Hat Enterprise Linux 9 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat OpenShift Container Platform 4 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat OpenShift Container Platform 4.13 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat OpenShift Container Platform 4.14 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat OpenShift Container Platform 4.15 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Red Hat | Red Hat OpenShift Container Platform 4.16 | versions not specified by the source | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Sonicwall | Sma 8200v Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Sonicwall | Sma6200 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Sonicwall | Sma6210 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Sonicwall | Sma7200 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Sonicwall | Sma7210 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Sonicwall | Sra Ex7000 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| SUSE | Linux Enterprise Micro | version 6.0 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 8.1 | CVSS 3.1 | High | 2.2 | 5.9 | secalert@redhat.com via NIST National Vulnerability Database |
| 8.1 | CVSS 3.1 | High | 2.2 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 8.1 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 8.1 | CVSS 3.1 | High | — | — | redhat via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Public exploits, PoCs and detection templates
Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.
Exploit-DB
- OpenSSH server (sshd) 9.8p1 - Race Condition Apr 22, 2025
Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.
EPSS over time FIRST
Oct 14, 2026 → Oct 15, 2026 · 2 reading(s) · max 99.51%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · red hat/red hat enterprise linux 9, red hat/red hat enterprise linux 9.0 update services for sap solutions, red hat/red
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · sonicwall/sma 6200 firmware, sonicwall/sma 7200 firmware, arista/eos, canonical/ubuntu linux, almalinux/almalinux, sonic
- CVSS changed · 8.1
- Source status changed · → Modified
- Record created in this database
- 2024
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 15, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
91 on the record
- news.ycombinator.com/item
- github.com/openela-main/openssh/commit/e1f438970e5a337a17070a637c1b9e19697cad09
- lists.mindrot.org/pipermail/openssh-unix-dev/2024-July/041431.html
- www.openwall.com/lists/oss-security/2024/07/03/3
- lists.mindrot.org/pipermail/openssh-unix-announce/2024-July/000158.html
- www.openwall.com/lists/oss-security/2024/07/11/1
- packetstorm.news/files/id/190587/
- www.theregister.com/2024/07/01/regresshion_openssh/
- www.openwall.com/lists/oss-security/2024/07/03/2
- www.openwall.com/lists/oss-security/2024/07/01/12
- archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openss
- www.openwall.com/lists/oss-security/2024/07/01/13
- www.openwall.com/lists/oss-security/2024/07/28/2
- support.apple.com/kb/HT214118
- security-tracker.debian.org/tracker/CVE-2024-6387
- lists.almalinux.org/archives/list/announce@lists.almalinux.org/thread/23BF5BMGFVEVUI2WNVA
- www.openwall.com/lists/oss-security/2024/07/02/1
- www.openwall.com/lists/oss-security/2024/07/09/2
- github.com/microsoft/azurelinux/issues/9555
- www.splunk.com/en_us/blog/security/cve-2024-6387-regresshion-vulnerability.html
- www.openwall.com/lists/oss-security/2024/07/08/2
- www.openwall.com/lists/oss-security/2024/07/04/2
- www.openwall.com/lists/oss-security/2024/07/09/5
- www.openwall.com/lists/oss-security/2024/07/03/5
- access.redhat.com/errata/RHSA-2024:4479
- github.com/oracle/oracle-linux/issues/149
- nvd.nist.gov/vuln/detail/CVE-2024-6387
- stackdiary.com/openssh-race-condition-in-sshd-allows-remote-code-execution
- www.openwall.com/lists/oss-security/2024/07/23/4
- www.vicarius.io/vsociety/posts/regresshion-an-openssh-regression-error-cve-2024-6387
- www.suse.com/security/cve/CVE-2024-6387.html
- www.openwall.com/lists/oss-security/2024/07/10/2
- www.akamai.com/blog/security-research/2024-openssh-vulnerability-regression-what-to-
- www.openwall.com/lists/oss-security/2024/07/03/1
- github.com/PowerShell/Win32-OpenSSH/discussions/2248
- github.com/AlmaLinux/updates/issues/629
- www.openwall.com/lists/oss-security/2024/07/03/4
- access.redhat.com/errata/RHSA-2024:4389
- www.theregister.com/2024/07/01/regresshion_openssh
- access.redhat.com/security/cve/CVE-2024-6387
- www.openwall.com/lists/oss-security/2024/07/28/3
- bugzilla.redhat.com/show_bug.cgi
- www.openwall.com/lists/oss-security/2024/07/10/6
- ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2024-002.txt.asc
- archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openss
- github.com/zgzhang/cve-2024-6387-poc
- www.openwall.com/lists/oss-security/2024/07/23/6
- security.netapp.com/advisory/ntap-20240701-0001/
- www.openwall.com/lists/oss-security/2024/07/03/11
- packetstorm.news/files/id/190587
- www.openwall.com/lists/oss-security/2024/07/11/3
- access.redhat.com/errata/RHSA-2024:4474
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2024-0010
- www.openwall.com/lists/oss-security/2024/07/10/1
- seclists.org/fulldisclosure/2024/Jul/19
- www.exploit-db.com/exploits/52269
- www.openssh.com/txt/release-9.8
- access.redhat.com/errata/RHSA-2024:4340
- seclists.org/fulldisclosure/2024/Jul/18
- github.com/rapier1/hpn-ssh/issues/87
- github.com/PowerShell/Win32-OpenSSH/issues/2249
- support.apple.com/kb/HT214120
- stackdiary.com/openssh-race-condition-in-sshd-allows-remote-code-execution/
- www.openwall.com/lists/oss-security/2024/07/04/1
- www.arista.com/en/support/advisories-notices/security-advisory/19904-security-adviso
- github.com/advisories/GHSA-2x8c-95vh-gfv4
- access.redhat.com/errata/RHSA-2024:4469
- www.openwall.com/lists/oss-security/2024/07/08/3
- sig-security.rocky.page/issues/CVE-2024-6387
- access.redhat.com/errata/RHSA-2024:4312
- lists.almalinux.org/archives/list/announce@lists.almalinux.org/thread/23BF5BMGFVEVUI2WNVA
- www.openwall.com/lists/oss-security/2024/07/10/3
- cert-portal.siemens.com/productcert/html/ssa-446545.html
- github.com/Azure/AKS/issues/4379
- www.freebsd.org/security/advisories/FreeBSD-SA-24:04.openssh.asc
- explore.alas.aws.amazon.com/CVE-2024-6387.html
- ubuntu.com/security/notices/USN-6859-1
- seclists.org/fulldisclosure/2024/Jul/20
- access.redhat.com/errata/RHSA-2024:4484
- www.openwall.com/lists/oss-security/2024/07/10/4
- sig-security.rocky.page/issues/CVE-2024-6387/
- blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthe
- ubuntu.com/security/CVE-2024-6387
- santandersecurityresearch.github.io/blog/sshing_the_masses.html
- www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt
- arstechnica.com/security/2024/07/regresshion-vulnerability-in-openssh-gives-attackers
- support.apple.com/kb/HT214119
- security.netapp.com/advisory/ntap-20240701-0001
- arstechnica.com/security/2024/07/regresshion-vulnerability-in-openssh-gives-attackers
- forum.vmssoftware.com/viewtopic.php
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-104045 Sssd: sssd: denial of service via race condition in autofs responder 9d
- Medium CVE-2026-104046 Sssd: sssd: denial of service via incomplete identity provider authentication requests 9d
- High CVE-2026-104048 Sssd: sssd: authorization bypass via cross-domain username collision in hbac evaluation 9d
- Medium CVE-2026-104047 Sssd: sssd: information disclosure via query injection in entra id lookups 9d
- High CVE-2026-102558 Libsoup: libsoup: heap buffer overflow during websocket receive-buffer growth 16d
- High CVE-2026-102555 Libsoup: libsoup: heap buffer overflow via uninitialized length in data-uri base64 decoding 16d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2024-6387 is "Openssh: regresshion - race condition in ssh allows rce/dos", rated High. It affects Almalinux (Almalinux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. EPSS 99.51% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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