In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted across authentication attempts.

ubuntu_linux USN-8928-1: Ubuntu 22.04 LTS / Ubuntu 24.04 LTS / Ubuntu 26.04 LTS : OpenSSH vulnerabilities (USN-8928-1)

The remote Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8928-1 advisory.

    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)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1792197391 advisory.

  - In sftp in OpenSSH before 10.6, a server can trigger directory traversal (causing files to be written to     unintended locations) during a recursive copy operation. (CVE-2026-106552)

  - In sshd in OpenSSH before 10.6, credentials can incorrectly persist after failure of a     GSSAPIAuthentication authentication attempt. (CVE-2026-106553)

  - In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted     across authentication attempts. (CVE-2026-106555)

  - In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is     contraindicated by the arXiv 2609.07709 Crossing the Streams findings. (CVE-2026-106582)

  - In ssh in OpenSSH before 10.6, a $ or \ character can occur in a command-line username, leading to     injection. (CVE-2026-106583)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted
    across authentication attempts. (CVE-2026-106555)

ID	Name	Product	Family	Type	Severity
367205	Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : OpenSSH vulnerabilities (USN-8928-1)	Nessus	Ubuntu Local Security Checks	Local	high
366706	AlmaLinux 9.2 [TuxCare] Security Update: openssh / openssh-askpass / openssh-clients / openssh-keycat / etc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1792197391)	Nessus	Alma Linux Local Security Checks	Local	high
473735	Echo: openssh: security update to 1:10.6p1-1	Tenable Cloud Security	Echo Local Security Checks	Local	high
473735	Echo: openssh: security update to 1:10.6p1-1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high

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