# What is CVE-2024-6387?

> CVE-2024-6387 is a high-severity flaw (CVSS 8.1) in OpenSSH from OpenBSD, published on 1 July 2024. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at over 99%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2024-6387

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 71 out of 100 (High); action: Patch now. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 8.1 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** over 99% (latest exploit-likelihood forecast)
- **Published:** 1 July 2024
- **Record last updated:** 1 September 2026
- **Main product:** OpenSSH from OpenBSD
- **Affected products:** 53

## What is CVE-2024-6387? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The official 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.

### What kind of flaw is it?

- CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- CWE-364: Signal Handler Race Condition

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Hard: conditions must line up
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Is CVE-2024-6387 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at over 99%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: >99%, >99%, >99%, >99%, >99%, >99%, >99%.

### Timeline

- 1 July 2024: Published
- 11 June 2025: Exploit likelihood fell
- 17 August 2025: Exploit likelihood jumped
- 1 September 2026: Record last updated

### How Precursor Intelligence ranks it

CVE-2024-6387 scores **71 out of 100 (High)**, with the action "Patch now".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2024-6387?

The published record lists 53 products. Versions are as published: "before 4.4" means every version up to, but not including, 4.4.

- [OpenSSH](https://www.precursorintelligence.com/product/openbsd/openssh) by [OpenBSD](https://www.precursorintelligence.com/vendors/openbsd) (Application): before 4.4, 4.4, 8.5-p1, 8.6 to 9.8
- [FreeBSD](https://www.precursorintelligence.com/product/freebsd/freebsd) by [FreeBSD](https://www.precursorintelligence.com/vendors/freebsd) (Operating system): 13.2, 13.2-p1, 13.2-p2, 13.2-p3, 13.2-p4, 13.2-p5, 13.2-p6, 13.2-p7, 13.2-p8, 13.2-p9, 13.2-p10, 13.2-p11, 13.3, 13.3-p1, 13.3-p2, 13.3-p3, 14.0-beta5, 14.0, 14.0-p1, 14.0-p2, 14.0-p3, 14.0-p4, 14.0-p5, 14.0-p6, 14.0-p7, 14.0-rc3, 14.0-rc4-p1, 14.1, 14.1-p1
- [Ubuntu Linux](https://www.precursorintelligence.com/product/canonical/ubuntu_linux) by [Canonical](https://www.precursorintelligence.com/vendors/canonical) (Operating system): 22.04, 22.10, 23.04, 23.10, 24.04
- [macOS](https://www.precursorintelligence.com/product/apple/macos) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Operating system): 12.0 to before 12.7.6, 13.0 to before 13.6.8, 14.0 to before 14.6
- [Ontap Tools](https://www.precursorintelligence.com/product/netapp/ontap_tools) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): 9, 10
- [500f Firmware](https://www.precursorintelligence.com/product/netapp/500f_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [8300 Firmware](https://www.precursorintelligence.com/product/netapp/8300_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [8700 Firmware](https://www.precursorintelligence.com/product/netapp/8700_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A150 Firmware](https://www.precursorintelligence.com/product/netapp/a150_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A1k Firmware](https://www.precursorintelligence.com/product/netapp/a1k_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A220 Firmware](https://www.precursorintelligence.com/product/netapp/a220_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A250 Firmware](https://www.precursorintelligence.com/product/netapp/a250_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A400 Firmware](https://www.precursorintelligence.com/product/netapp/a400_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A70 Firmware](https://www.precursorintelligence.com/product/netapp/a70_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A700s Firmware](https://www.precursorintelligence.com/product/netapp/a700s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A800 Firmware](https://www.precursorintelligence.com/product/netapp/a800_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A90 Firmware](https://www.precursorintelligence.com/product/netapp/a90_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A900 Firmware](https://www.precursorintelligence.com/product/netapp/a900_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [A9500 Firmware](https://www.precursorintelligence.com/product/netapp/a9500_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Active Iq Unified Manager](https://www.precursorintelligence.com/product/netapp/active_iq_unified_manager) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Almalinux](https://www.precursorintelligence.com/product/almalinux/almalinux) by [Almalinux](https://www.precursorintelligence.com/vendors/almalinux) (Operating system): 9.0
- [Amazon Linux](https://www.precursorintelligence.com/product/amazon/amazon_linux) by [Amazon](https://www.precursorintelligence.com/vendors/amazon) (Operating system): 2023.0
- [Bootstrap OS](https://www.precursorintelligence.com/product/netapp/bootstrap_os) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [C190 Firmware](https://www.precursorintelligence.com/product/netapp/c190_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [C250 Firmware](https://www.precursorintelligence.com/product/netapp/c250_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [C400 Firmware](https://www.precursorintelligence.com/product/netapp/c400_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [C800 Firmware](https://www.precursorintelligence.com/product/netapp/c800_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 12.0
- [E-Series Santricity OS Controller](https://www.precursorintelligence.com/product/netapp/e-series_santricity_os_controller) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): 11.0.0 to 11.70.2
- [Enterprise Linux](https://www.precursorintelligence.com/product/redhat/enterprise_linux) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.0
- [Enterprise Linux Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.4
- [Enterprise Linux for Arm 64](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_arm_64) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.0_aarch64
- [Enterprise Linux for Arm 64 Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_arm_64_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.4_aarch64
- [Enterprise Linux for Ibm Z Systems](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.0_s390x
- [Enterprise Linux for Ibm Z Systems Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.4_s390x
- [Enterprise Linux for Power Little Endian](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_power_little_endian) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.0_ppc64le
- [Enterprise Linux for Power Little Endian Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_power_little_endian_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.4_ppc64le
- [Enterprise Linux Server Aus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_aus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.4
- [Eos](https://www.precursorintelligence.com/product/arista/eos) by [Arista](https://www.precursorintelligence.com/vendors/arista) (Operating system): 4.32.0 to 4.32.1f
- [Fas2720 Firmware](https://www.precursorintelligence.com/product/netapp/fas2720_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Fas2750 Firmware](https://www.precursorintelligence.com/product/netapp/fas2750_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Fas2820 Firmware](https://www.precursorintelligence.com/product/netapp/fas2820_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Linux Enterprise Micro](https://www.precursorintelligence.com/product/suse/linux_enterprise_micro) by [Suse](https://www.precursorintelligence.com/vendors/suse) (Operating system): 6.0
- [NetBSD](https://www.precursorintelligence.com/product/netbsd/netbsd) by [NetBSD](https://www.precursorintelligence.com/vendors/netbsd) (Operating system): up to 10.0.0
- [Ontap](https://www.precursorintelligence.com/product/netapp/ontap) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): 9
- [Ontap Select Deploy Administration Utility](https://www.precursorintelligence.com/product/netapp/ontap_select_deploy_administration_utility) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Openshift Container Platform](https://www.precursorintelligence.com/product/redhat/openshift_container_platform) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 4.0
- [Sma 6200 Firmware](https://www.precursorintelligence.com/product/sonicwall/sma_6200_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified
- [Sma 6210 Firmware](https://www.precursorintelligence.com/product/sonicwall/sma_6210_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified
- [Sma 7200 Firmware](https://www.precursorintelligence.com/product/sonicwall/sma_7200_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified
- [Sma 7210 Firmware](https://www.precursorintelligence.com/product/sonicwall/sma_7210_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified
- [Sma 8200v Firmware](https://www.precursorintelligence.com/product/sonicwall/sma_8200v_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified
- [Sra EX 7000 Firmware](https://www.precursorintelligence.com/product/sonicwall/sra_ex_7000_firmware) by [SonicWall](https://www.precursorintelligence.com/vendors/sonicwall) (Operating system): version not specified

## How do I fix CVE-2024-6387?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/3) (Mailing list, Patch)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4312) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4340) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4389) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4469) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4474) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4479) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2024:4484) (Third-party advisory)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2024-6387) (Third-party advisory)
- [bugzilla.redhat.com](https://bugzilla.redhat.com/show_bug.cgi?id=2294604) (Third-party advisory)
- [santandersecurityresearch.github.io](https://santandersecurityresearch.github.io/blog/sshing_the_masses.html) (Exploit, Third-party advisory)
- [openssh.com](https://www.openssh.com/txt/release-9.8) (Release notes, Third-party advisory)
- [qualys.com](https://www.qualys.com/2024/07/01/cve-2024-6387/regresshion.txt) (Exploit, Third-party advisory)
- [seclists.org](http://seclists.org/fulldisclosure/2024/Jul/18) (Mailing list)
- [seclists.org](http://seclists.org/fulldisclosure/2024/Jul/19) (Mailing list)
- [seclists.org](http://seclists.org/fulldisclosure/2024/Jul/20) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/01/12) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/01/13) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/02/1) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/1) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/11) (Exploit, Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/2) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/4) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/03/5) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/04/1) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/04/2) (Exploit, Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/08/2) (Exploit, Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/08/3) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/09/2) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/09/5) (Exploit, Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/10/1) (Exploit, Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/10/2) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/10/3) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/10/4) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/10/6) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/11/1) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/11/3) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/23/4) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/23/6) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/28/2) (Mailing list)
- [openwall.com](http://www.openwall.com/lists/oss-security/2024/07/28/3) (Mailing list)
- [archlinux.org](https://archlinux.org/news/the-sshd-service-needs-to-be-restarted-after-upgrading-to-openssh-98p1/) (Third-party advisory)

## Questions

### What is CVE-2024-6387?

CVE-2024-6387 is a high-severity flaw in OpenSSH from OpenBSD, published on 1 July 2024. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2024-6387?

It scores 8.1 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2024-6387 is 71 out of 100, which is High. Its action is "Patch now". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2024-6387 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at over 99%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2024-6387 affect?

For OpenSSH from OpenBSD: before 4.4, 4.4, 8.5-p1, 8.6 to 9.8. The record lists 53 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2024-6387?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2024-6387 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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