Improper access control in OpenSSH - CVE-2026-59999

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Main Vulnerability Database Vulnerabilities #VU137701

Improper access control in OpenSSH - CVE-2026-59999

Published: July 15, 2026


Vulnerability identifier: #VU137701
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59999
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to enable tunneling despite forwarding restrictions.

The vulnerability exists due to improper access control in sshd(8) when DisableForwarding=yes and PermitTunnel=yes are configured together. A remote privileged user can use tunneling despite forwarding restrictions to enable tunneling despite forwarding restrictions.

Exploitation requires configurations where PermitTunnel is enabled.


Affected software

OpenSSH
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Basesystem Module
Desktop Applications Module
openSUSE Leap
openEuler
Ubuntu
Anolis OS
pam_ssh_agent_auth
openssh
openssh-askpass
openssh-cavs
openssh-clients
openssh-help
openssh-debuginfo
openssh-server
openssh-ldap
openssh-keycat
openssh-debugsource
openssh (Ubuntu package)
openssh-doc
openssh-sk-dummy
openssh-server-config-disallow-rootlogin
openssh-helpers-debuginfo
openssh-common
openssh-fips
openssh-clients-debuginfo
openssh-helpers
openssh-common-debuginfo
openssh-server-debuginfo
openssh-askpass-gnome-debuginfo
openssh-askpass-gnome
openssh-askpass-gnome-debugsource
openssh-cavs-debuginfo

How to mitigate CVE-2026-59999

Install security update from vendor's website.

OpenSSH - update to 10.4p1
pam_ssh_agent_auth - addressed in versions 0.10.3-9.39, 0.10.4-4.46, 0.10.4-5.17, 0.10.4-5.22
openssh - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-askpass - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-cavs - update to 8.2p1-39
openssh-clients - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-help - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-debuginfo - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-server - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-ldap - update to 8.2p1-39
openssh-keycat - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh-debugsource - addressed in versions 8.2p1-39, 8.8p1-46, 9.6p1-17, 9.6p1-22
openssh (Ubuntu package) - addressed in versions 1:8.9p1-3ubuntu0.16, 1:9.6p1-3ubuntu13.18, 1:10.2p1-2ubuntu3.4
openssh-doc - update to 9.6p1-11
openssh-sk-dummy - update to 9.6p1-11
openssh-server - update to 9.6p1-11
openssh-keycat - update to 9.6p1-11
openssh-clients - update to 9.6p1-11
openssh-askpass - update to 9.6p1-11
openssh - update to 9.6p1-11
openssh-server - update to 9.6p1-150600.6.49.1
openssh-server-config-disallow-rootlogin - update to 9.6p1-150600.6.49.1
openssh-helpers-debuginfo - update to 9.6p1-150600.6.49.1
openssh-debugsource - update to 9.6p1-150600.6.49.1
openssh-debuginfo - update to 9.6p1-150600.6.49.1
openssh-common - update to 9.6p1-150600.6.49.1
openssh-fips - update to 9.6p1-150600.6.49.1
openssh-clients-debuginfo - update to 9.6p1-150600.6.49.1
openssh-helpers - update to 9.6p1-150600.6.49.1
openssh-clients - update to 9.6p1-150600.6.49.1
openssh-common-debuginfo - update to 9.6p1-150600.6.49.1
openssh-server-debuginfo - update to 9.6p1-150600.6.49.1
openssh - update to 9.6p1-150600.6.49.1
openssh-askpass-gnome-debuginfo - update to 9.6p1-150600.6.49.1
openssh-askpass-gnome - update to 9.6p1-150600.6.49.1
openssh-askpass-gnome-debugsource - update to 9.6p1-150600.6.49.1
openssh-cavs - update to 9.6p1-150600.6.49.1
openssh-cavs-debuginfo - update to 9.6p1-150600.6.49.1

External References

Related Security Bulletins