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Fencer Vulns
medium 4.8

CVE-2023-6004 json

Libssh: proxycommand/proxyjump features allow injection of malicious code through hostname

published 2024-01-03 2 y ago modified 2026-11-06 2 d ago also EUVD-2023-58271

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

A flaw was found in libssh. By utilizing the ProxyCommand or ProxyJump feature, users can exploit unchecked hostname syntax on the client. This issue may allow an attacker to inject malicious code into the command of the features mentioned through the hostname parameter.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 8 0:0.9.6-14.el8
  • Red Hat Red Hat Enterprise Linux 9 0:0.10.4-13.el9
  • libssh Debian 12 0.10.6-0+deb12u1
  • libssh Debian 14, Debian 13 0.10.6-1

debian advisories DEBIAN-CVE-2023-6004

  • libssh Ubuntu 20.04 LTS 0.9.3-2ubuntu2.5
  • libssh Ubuntu 22.04 LTS 0.9.6-2ubuntu0.22.04.3
  • libssh Ubuntu Pro 16.04 LTS 0.6.3-4.3ubuntu0.6+esm1
  • libssh Ubuntu Pro 18.04 LTS 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm3

ubuntu advisories UBUNTU-CVE-2023-6004

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh RHEL 8 0.9.6-14.el8
  • libssh-config RHEL 8 0.9.6-14.el8
  • libssh RHEL 9 0.10.4-13.el9
  • libssh-config RHEL 9 0.10.4-13.el9

red hat advisories RHSA-2024:3233RHSA-2024:2504

  • libssh SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 0.9.8-3.12.2
  • libssh SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +6 more 0.9.8-150200.13.3.1
  • libssh SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Real Time 15 SP4 +11 more 0.9.8-150400.3.3.1

suse advisories SUSE-SU-2024:0539-1SUSE-SU-2024:0525-1SUSE-SU-2024:0140-1

  • libssh openSUSE Tumbleweed 0.10.6-1.1

opensuse advisories openSUSE-SU-2024:13638-1

  • libssh AlmaLinux 8 0.9.6-14.el8
  • libssh-config AlmaLinux 8 0.9.6-14.el8
  • libssh AlmaLinux 9 0.10.4-13.el9
  • libssh-config AlmaLinux 9 0.10.4-13.el9

almalinux advisories ALSA-2024:3233ALSA-2024:2504

  • libssh Rocky Linux 9 0.10.4-13.el9
  • libssh Rocky Linux 8 0.9.6-14.el8

rocky linux advisories RLSA-2024:2504RLSA-2024:3233

  • libssh Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 0.10.6-r0

alpine advisories ALPINE-CVE-2023-6004

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh Azure Linux 3.0 0.10.6-1

azure linux advisories AZL-34942

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-6004 updated cvss 4.8

libssh: ProxyCommand/ProxyJump features allow injection of malicious code through hostname

  • Red Hat Enterprise Linux 7 libssh
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) libssh-devel 0.9.6-14.el8, libssh-debuginfo 0.9.6-14.el8, libssh-debugsource 0.9.6-14.el8
    fixed: vendor fix RHSA-2024:3233
  • Red Hat Enterprise Linux AppStream (v. 9) libssh-devel 0.10.4-13.el9, libssh-debuginfo 0.10.4-13.el9, libssh-debugsource 0.10.4-13.el9
    fixed: vendor fix RHSA-2024:2504
  • Red Hat Enterprise Linux BaseOS (v. 8) libssh 0.9.6-14.el8, libssh-config 0.9.6-14.el8
    fixed: vendor fix RHSA-2024:3233
  • Red Hat Enterprise Linux BaseOS (v. 9) libssh 0.10.4-13.el9, libssh-config 0.10.4-13.el9
    fixed: vendor fix RHSA-2024:2504

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L
NVD 3.1 4.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L

Affected products

  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

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.