CVE-2023-42818: JumpServer is an open source bastion host

Routine

MEDIUM 5.4UPGRADE

CVE-2023-42818 is a medium-severity flaw (CVSS 5.4) affecting jumpserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

JumpServer is an open source bastion host. When users enable MFA and use a public key for authentication, the Koko SSH server does not verify the corresponding SSH private key. An attacker could exploit a vulnerability by utilizing a disclosed public key to attempt brute-force authentication against the SSH service This issue has been patched in versions 3.6.5 and 3.5.6. Users are advised to upgrade. There are no known workarounds for this issue.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-287, CWE-307
Published	2023-09-27
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: fit2cloud

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-09-27 21:15 UTCPublished CVE record published
2026-06-17 06:24 UTCUpdated Record last modified

fit2cloud jumpserver UPGRADE

Affected: < 3.5.6 · >= 3.6.0 and < 3.6.5

Fixed in: 3.5.6, 3.6.5

Safe to downgrade to: a release before 3.6.0

1. Check installed version

apt-cache policy jumpserver || rpm -q jumpserver || jumpserver --version

2. UPGRADE to 3.5.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade jumpserver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade jumpserver

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.6.0 (Debian / Ubuntu)

apt-cache madison jumpserver sudo apt install jumpserver=<VERSION_BEFORE_3.6.0> sudo apt-mark hold jumpserver

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list jumpserver sudo dnf downgrade jumpserver-<VERSION_BEFORE_3.6.0> sudo dnf versionlock add jumpserver

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2023-42818?

jumpserver: upgrade to 3.5.6, 3.6.5. Exact commands for each OS are on this page.

Is CVE-2023-42818 being exploited?

CVE-2023-42818 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-2023-42818 affect?

CVE-2023-42818 affects jumpserver. Severity is medium (CVSS 5.4). JumpServer is an open source bastion host. When users enable MFA and use a public key for authentication, the Koko SSH server does not verify the corresponding SSH private key. An attacker could exploit a vulnerability by utilizing a disclo

How urgent is CVE-2023-42818?

Priority 37/100. Public exploit reference

Related CVEs

CVE-2025-62712 CRITICAL 9.6 UPGRADE JumpServer is an open source bastion host and an operation and maintenance security audit system
CVE-2025-62795 HIGH 7.1 UPGRADE JumpServer is an open source bastion host and an operation and maintenance security audit system
CVE-2023-48193 CRITICAL 9.8 DOWNGRADE Insecure Permissions vulnerability in JumpServer GPLv3 v.3.8.0 allows a remote attacker to execute arbitrary c
CVE-2026-31864 MEDIUM 6.8 UPGRADE JumpServer is an open source bastion host and an operation and maintenance security audit system
CVE-2026-31798 MEDIUM 5.0 UPGRADE JumpServer is an open source bastion host and an operation and maintenance security audit system

References

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