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Fencer Vulns
medium 5.4

CVE-2023-42818 json

SSH public key login without private key challenge if mfa is enabled in jumpserver

published 2023-09-27 3 y ago modified 2026-06-17 4 mo ago also GHSA-jv3c-27cv-w8jv , GO-2025-3570 , EUVD-2023-47240

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/jumpserver/jumpserver 3.5.6+incompatible, 3.6.5+incompatible
  • jumpserver jumpserver 3.5.6, 3.6.5
  • govulncheck-vulndb openSUSE Tumbleweed 0.0.20250612T141001-1.1

opensuse advisories openSUSE-SU-2025:15225-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/jumpserver/jumpserver/security/advisories/GHSA-jv3c-27cv-w8jv referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/jumpserver/koko
all versions
 no fix listed
go github.com/jumpserver/jumpserver
<3.5.6+incompatible
>=3.6.0+incompatible, <3.6.5+incompatible
3.5.6+incompatible
3.6.5+incompatible

Affected products

  • jumpserver jumpserver

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-307 Improper Restriction of Excessive Authentication Attempts

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.