Home / mailings [USN-8937-1] OpenSSH vulnerabilities
Posted on 19 October 2026
Ubuntu Security==========================================================================Ubuntu Security Notice USN-8937-1
October 19, 2026
openssh, openssh-gssapi vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 26.10
Summary:
Several security issues were fixed in OpenSSH.
Software Description:
- openssh: secure shell (SSH) for secure access to remote machines
- openssh-gssapi: secure shell (SSH) for secure access to remote machines
Details:
It was discovered that OpenSSH's sftp client incorrectly handled paths
returned by the server during a recursive copy operation. A remote attacker
controlling the server could possibly use this issue to write files to
unintended locations. (CVE-2026-106552)
It was discovered that OpenSSH's sshd server incorrectly handled
GSSAPIAuthentication state across authentication attempts. An attacker
could possibly use this issue to obtain credentials from a previous failed
authentication attempt. (CVE-2026-106553, CVE-2026-106555)
It was discovered that OpenSSH incorrectly used an LZ77 dictionary coder
during compression. An attacker could possibly use this issue to obtain
sensitive information. (CVE-2026-106582)
It was discovered that OpenSSH's ssh client incorrectly allowed special
characters in command-line usernames. An attacker could possibly use this
issue to inject arbitrary commands via specially crafted usernames.
(CVE-2026-106583)
It was discovered that OpenSSH's ssh-keygen incorrectly handled Daylight
Saving Time when converting dates. An attacker could possibly use this
issue to cause certificates to have incorrect expiration times.
(CVE-2026-106584)
It was discovered that OpenSSH did not check whether the maximum packet
length was exceeded during decompression. A remote attacker could possibly
use this issue to cause a denial of service. (CVE-2026-106585)
It was discovered that OpenSSH's sshd server incorrectly applied the
restrict keyword from authorized_keys to tunnel forwarding requests. A
local attacker with an authorized key could possibly use this issue to
bypass intended tunnel forwarding restrictions. (CVE-2026-106586)
It was discovered that OpenSSH's sshd server incorrectly handled certain
configuration options that accept a "none" value. An attacker could
possibly use this issue to cause OpenSSH to behave unexpectedly.
(CVE-2026-106587)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 26.10
openssh-client 1:10.5p1-1ubuntu3.1
openssh-client-gssapi 1:10.5p1-1ubuntu3.1
openssh-server 1:10.5p1-1ubuntu3.1
openssh-server-gssapi 1:10.5p1-1ubuntu3.1
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8937-1
CVE-2026-106552, CVE-2026-106553, CVE-2026-106555, CVE-2026-106582,
CVE-2026-106583, CVE-2026-106584, CVE-2026-106585, CVE-2026-106586,
CVE-2026-106587
Package Information:
https://launchpad.net/ubuntu/+source/openssh/1:10.5p1-1ubuntu3.1
https://launchpad.net/ubuntu/+source/openssh-gssapi/1:10.5p1-1ubuntu3.1
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