USN-8090-2: OpenSSH vulnerabilities
Publication date
12 March 2026
Overview
Several security issues were fixed in OpenSSH.
Releases
Packages
- openssh - secure shell (SSH) for secure access to remote machines
Details
USN-8090-1 fixed vulnerabilities in OpenSSH. This update provides the
corresponding updates for Ubuntu 20.04 LTS.
Original advisory details:
Jeremy Brown discovered that the OpenSSH GSSAPI Key Exchange incorrectly
handled disconnecting clients. In non-default configurations where the
GSSAPIKeyExchange setting is enabled, a remote attacker could use this
issue to cause OpenSSH to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2026-3497)
David Leadbeater discovered that OpenSSH incorrectly handled certain
control characters in usernames. When untrusted usernames and the
ProxyCommand are being used, an attacker could possibly use this issue to
execute arbitrary code. (CVE-2025-61984)
David Leadbeater discovered that OpenSSH incorrectly handled NULL
characters in ssh:// URIs. When the ProxyCommand is being...
USN-8090-1 fixed vulnerabilities in OpenSSH. This update provides the
corresponding updates for Ubuntu 20.04 LTS.
Original advisory details:
Jeremy Brown discovered that the OpenSSH GSSAPI Key Exchange incorrectly
handled disconnecting clients. In non-default configurations where the
GSSAPIKeyExchange setting is enabled, a remote attacker could use this
issue to cause OpenSSH to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2026-3497)
David Leadbeater discovered that OpenSSH incorrectly handled certain
control characters in usernames. When untrusted usernames and the
ProxyCommand are being used, an attacker could possibly use this issue to
execute arbitrary code. (CVE-2025-61984)
David Leadbeater discovered that OpenSSH incorrectly handled NULL
characters in ssh:// URIs. When the ProxyCommand is being used, an attacker
could possibly use this issue to execute arbitrary code. (CVE-2025-61985)
Update instructions
In general, a standard system update will make all the necessary changes.
Learn more about how to get the fixes.The problem can be corrected by updating your system to the following package versions:
| Ubuntu Release | Package Version | ||
|---|---|---|---|
| 20.04 LTS focal | openssh-client – 1:8.2p1-4ubuntu0.13+esm1 | ||
| openssh-server – 1:8.2p1-4ubuntu0.13+esm1 | |||
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