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Fencer Vulns
medium 6.5

CVE-2023-1667 json

A NULL pointer dereference was found In libssh during re-keying with algorithm guessing.

published 2023-05-26 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-23895

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

A NULL pointer dereference was found In libssh during re-keying with algorithm guessing. This issue may allow an authenticated client to cause a denial of service.

Patch / fix

  • libssh Debian 14, Debian 13, Debian 12 0.10.5-1

debian advisories DEBIAN-CVE-2023-1667

  • libssh Ubuntu 20.04 LTS 0.9.3-2ubuntu2.3
  • libssh Ubuntu 22.04 LTS 0.9.6-2ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2023-1667

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 9 0.10.4-11.el9
  • libssh-config RHEL 9 0.10.4-11.el9
  • libssh RHEL 8 0.9.6-10.el8_8
  • libssh-config RHEL 8 0.9.6-10.el8_8
  • libssh RHEL 8.6 EUS 0.9.6-4.el8_6
  • libssh-config RHEL 8.6 EUS 0.9.6-4.el8_6

red hat advisories RHSA-2024:0538RHSA-2023:6643RHSA-2023:3839

  • 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 0.10.5-1.1

opensuse advisories openSUSE-SU-2024:12914-1

  • libssh AlmaLinux 9 0.10.4-11.el9
  • libssh-config AlmaLinux 9 0.10.4-11.el9
  • libssh AlmaLinux 8 0.9.6-10.el8_8
  • libssh-config AlmaLinux 8 0.9.6-10.el8_8

almalinux advisories ALSA-2023:6643ALSA-2023:3839

  • libssh Rocky Linux 8 0.9.6-10.el8_8

rocky linux advisories RLSA-2023:3839

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-2023-1667 updated cvss 4.3

libssh: NULL pointer dereference during rekeying with algorithm guessing

  • Red Hat Enterprise Linux 7 libssh
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) libssh-devel 0.9.6-10.el8_8, libssh-debuginfo 0.9.6-10.el8_8, libssh-debugsource 0.9.6-10.el8_8
    fixed: vendor fix RHSA-2023:3839
  • Red Hat Enterprise Linux AppStream (v. 9) libssh-devel 0.10.4-11.el9, libssh-debuginfo 0.10.4-11.el9, libssh-debugsource 0.10.4-11.el9
    fixed: vendor fix RHSA-2023:6643
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) libssh-devel 0.9.6-4.el8_6, libssh-debuginfo 0.9.6-4.el8_6, libssh-debugsource 0.9.6-4.el8_6
    fixed: vendor fix RHSA-2024:0538
  • Red Hat Enterprise Linux BaseOS (v. 8) libssh 0.9.6-10.el8_8, libssh-config 0.9.6-10.el8_8
    fixed: vendor fix RHSA-2023:3839
  • Red Hat Enterprise Linux BaseOS (v. 9) libssh 0.10.4-11.el9, libssh-config 0.10.4-11.el9
    fixed: vendor fix RHSA-2023:6643
  • Red Hat Enterprise Linux BaseOS EUS (v.8.6) libssh 0.9.6-4.el8_6, libssh-config 0.9.6-4.el8_6
    fixed: vendor fix RHSA-2024:0538
  • Red Hat Virtualization 4 ansible-collection-ansible-netcommon
    not affected: vulnerable code not present

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

Exploit prediction

1.31% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • n/a libssh

Classification

Weakness

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.