CVE-2024-6387: A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd)

Q: How do I fix CVE-2024-6387?

sma 6200 firmware: mitigate or apply the listed mitigation; sma 7200 firmware: mitigate or apply the listed mitigation; eos: upgrade to newer than 4.32.1f. Exact commands for each OS are on this page.

Q: Is CVE-2024-6387 being exploited?

CVE-2024-6387 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2024-6387 affect?

CVE-2024-6387 affects sma 6200 firmware, sma 7200 firmware, eos. Severity is high (CVSS 8.1). 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 fail

Q: How urgent is CVE-2024-6387?

Priority 68/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

HIGH 8.1REMOTEWATCHLISTMITIGATEMITIGATEUPGRADE

CVE-2024-6387 is a high-severity flaw (CVSS 8.1) affecting sma 6200 firmware, sma 7200 firmware, eos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	99.5% (top 1%)
CISA exploited list	No
Weakness	CWE-364, CWE-362
Published	2024-07-01
Last modified	2026-10-15

Publisher (CNA): Red Hat, Inc. · Vendor: almalinux · arista · canonical · sonicwall

Last updated 2026-10-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-07-01 13:15 UTCPublished CVE record published
2026-10-15 03:17 UTCUpdated Record last modified

sonicwall sma 6200 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

sonicwall sma 7200 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

arista eos UPGRADE

Affected: >= 4.32.0 and <= 4.32.1f

Fixed in: newer than 4.32.1f

Safe to downgrade to: a release before 4.32.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

canonical ubuntu linux MITIGATE

Affected: 23.10 · 24.04 · 22.04 · 22.10 · 23.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 22.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

almalinux almalinux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

sonicwall sma 6210 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora ELN · gram_grep · FIXED · 0.10.4-1.eln159 · FEDORA-2026-0808475f2a · source

sudo dnf upgrade --advisory=FEDORA-2026-0808475f2a

Fedora 46 · wesnoth · FIXED · 1.19.29-1.fc46 · FEDORA-2026-58f458e24e · source

sudo dnf upgrade --advisory=FEDORA-2026-58f458e24e

Ubuntu 22.04 · openssh · FIXED · 1:8.9p1-3ubuntu0.10

sudo apt update && sudo apt install --only-upgrade openssh dpkg --compare-versions "$(dpkg-query -W -f='${Version}' openssh)" ge "1:8.9p1-3ubuntu0.10" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · openssh · FIXED · 1:9.6p1-3ubuntu13.3

sudo apt update && sudo apt install --only-upgrade openssh dpkg --compare-versions "$(dpkg-query -W -f='${Version}' openssh)" ge "1:9.6p1-3ubuntu13.3" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · openssh · NOT AFFECTED

Ubuntu 20.04 · openssh-ssh1 · NOT AFFECTED

Ubuntu 22.04 · openssh-ssh1 · NOT AFFECTED

Debian 12 · openssh · FIXED · 1:9.2p1-2+deb12u3

sudo apt update && sudo apt install --only-upgrade openssh dpkg --compare-versions "$(dpkg-query -W -f='${Version}' openssh)" ge "1:9.2p1-2+deb12u3" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · openssh · FIXED · 1:9.7p1-7

sudo apt update && sudo apt install --only-upgrade openssh dpkg --compare-versions "$(dpkg-query -W -f='${Version}' openssh)" ge "1:9.7p1-7" && echo PATCHED || echo STILL-VULNERABLE

RHEL 9 · openssh · FIXED · openssh-8.7p1-38.el9_4.1

sudo dnf upgrade --advisory=RHSA-2024:4312 rpm -q openssh

RHEL 9.0 Update Services for SAP Solutions · openssh · FIXED · openssh-8.7p1-12.el9_0.1

sudo dnf upgrade --advisory=RHSA-2024:4389 rpm -q openssh

RHEL 9.2 Extended Update Support · openssh · FIXED · openssh-8.7p1-30.el9_2.4

sudo dnf upgrade --advisory=RHSA-2024:4340 rpm -q openssh

RHEL 10 · openssh · NOT AFFECTED

RHEL 6 · openssh · NOT AFFECTED

Alpine 3.20 · openssh · FIXED · openssh-9.7_p1-r4

apk add --upgrade openssh apk info -v openssh

Alpine 3.21 · openssh · FIXED · openssh-9.8_p1-r0

apk add --upgrade openssh apk info -v openssh

Alpine 3.22 · openssh · FIXED · openssh-9.8_p1-r0

apk add --upgrade openssh apk info -v openssh

Alpine 3.23 · openssh · FIXED · openssh-9.8_p1-r0

apk add --upgrade openssh apk info -v openssh

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2024-649 · source

sudo dnf update --advisory=ALAS2023-2024-649

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: xaitax/CVE-2024-6387_Check (527 stars)
GitHub PoC: zgzhang/cve-2024-6387-poc (497 stars)
GitHub PoC: acrono/cve-2024-6387-poc (375 stars)
Write-up: blog.qualys.com/vulnerabilities-threat-research/2024/07/01/regresshion-remote-unauthentica
Write-up: cert-portal.siemens.com/productcert/html/ssa-082556.html
GitHub PoC: 0x4D31/cve-2024-6387_hassh
GitHub PoC: 3yujw7njai/CVE-2024-6387
Exploit-DB: OpenSSH server (sshd) 9.8p1 - Race Condition

Advisories and coverage

Official advisories

CERT-FR Alerts: Vulnérabilité dans OpenSSH (01 juillet 2024) 2024-07-01

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2024-6387?

sma 6200 firmware: mitigate or apply the listed mitigation; sma 7200 firmware: mitigate or apply the listed mitigation; eos: upgrade to newer than 4.32.1f. Exact commands for each OS are on this page.

Is CVE-2024-6387 being exploited?

CVE-2024-6387 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2024-6387 affect?

CVE-2024-6387 affects sma 6200 firmware, sma 7200 firmware, eos. Severity is high (CVSS 8.1). 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 fail

How urgent is CVE-2024-6387?

Priority 68/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

OpenSSH vulnerabilities · Ubuntu vulnerabilities · SonicWall vulnerabilities

References

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