Improper Check or Handling of Exceptional Conditions in libssh - CVE-2026-59845

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU139524

Improper Check or Handling of Exceptional Conditions in libssh - CVE-2026-59845

Published: July 27, 2026


Vulnerability identifier: #VU139524
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59845
CWE-ID: CWE-703
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper handling of fork() failure in ProxyCommand execution in the libssh client when cleaning up a session after executing a ProxyCommand. A local user can trigger a fork() failure and then cause the process to send a KILL signal to process group -1 to cause a denial of service.

This issue affects the client only and typically occurs under low-memory conditions.


Affected software

libssh
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Basesystem Module
openSUSE Leap
openEuler
Ubuntu
Anolis OS
libssh
libssh-debuginfo
libssh-debugsource
libssh-devel
libssh-help
libssh (Ubuntu package)
libssh4-32bit-debuginfo
libssh4-64bit
libssh4-64bit-debuginfo
libssh4-32bit
libssh4
libssh-config
libssh4-debuginfo
libssh (Red Hat package)
libssh-doc
Netezza Appliance - Cyclops

How to mitigate CVE-2026-59845

Install security update from vendor's website.

libssh - addressed in versions 0.11.5, 0.12.1
libssh - addressed in versions 0.9.4-21, 0.9.6-21, 0.10.5-15
libssh-debuginfo - addressed in versions 0.9.4-21, 0.9.6-21, 0.10.5-15
libssh-debugsource - addressed in versions 0.9.4-21, 0.9.6-21, 0.10.5-15
libssh-devel - addressed in versions 0.9.4-21, 0.9.6-21, 0.10.5-15
libssh-help - addressed in versions 0.9.4-21, 0.9.6-21, 0.10.5-15
libssh (Ubuntu package) - addressed in versions 0.9.6-2ubuntu0.22.04.8, 0.10.6-2ubuntu0.5, 0.11.3-1ubuntu2.1
libssh4-32bit-debuginfo - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh4-64bit - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh4-64bit-debuginfo - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh4-32bit - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh4 - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh-debugsource - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh-config - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh-devel - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh4-debuginfo - addressed in versions 0.9.8-150400.3.20.1, 0.9.8-150600.11.15.1
libssh (Red Hat package) - addressed in versions 0.10.4-19.el9_8, 0.12.0-3.el10_2
libssh-devel - update to 0.10.5-15
libssh - update to 0.10.5-15
libssh-config - update to 0.10.5-15
libssh-doc - update to 0.10.5-15
Netezza Appliance - Cyclops - update to 11.3.1.4

External References

Related Security Bulletins