Input validation error in libssh - CVE-2026-59844

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Main Vulnerability Database Vulnerabilities #VU139527

Input validation error in libssh - CVE-2026-59844

Published: July 27, 2026


Vulnerability identifier: #VU139527
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59844
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to improper input validation in the libssh SFTP server when processing SSH_FXP_READ requests. A remote user can send a specially crafted SSH_FXP_READ request with an excessive read length value to cause a denial of service.

The issue can be sustained by repeatedly issuing large read requests simultaneously over multiple SFTP channels.


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
libssh
libssh-debuginfo
libssh-debugsource
libssh-devel
libssh-help
libssh (Ubuntu package)
libssh4-32bit
libssh4-64bit
libssh4-64bit-debuginfo
libssh4-32bit-debuginfo
libssh4
libssh4-debuginfo
libssh-config
libssh (Red Hat package)

How to mitigate CVE-2026-59844

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 - 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-debuginfo - 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
libssh4-debuginfo - 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
libssh (Red Hat package) - addressed in versions 0.10.4-19.el9_8, 0.12.0-3.el10_2

External References

Related Security Bulletins