OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 09b7cd39-47bd-11ee-8e38-002590c1f29c advisory.

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in     the default configuration, to jump to any location in the sshd address space. One third-party report     states remote code execution is theoretically possible. (CVE-2023-25136)

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

According to the versions of the openssh packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities :

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in     the default configuration, to jump to any location in the sshd address space. One third-party report     states 'remote code execution is theoretically possible.' (CVE-2023-25136)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote host is affected by the vulnerability described in GLSA-202307-01 (OpenSSH: Remote Code Execution)

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in     the default configuration, to jump to any location in the sshd address space. One third-party report     states remote code execution is theoretically possible. (CVE-2023-25136)

  - ssh-add in OpenSSH before 9.3 adds smartcard keys to ssh-agent without the intended per-hop destination     constraints. The earliest affected version is 8.9. (CVE-2023-28531)

  -  Please review the CVE identifiers referenced below for details.  (CVE-2023-38408)

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

According to the versions of the openssh packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in     the default configuration, to jump to any location in the sshd address space. One third-party report     states 'remote code execution is theoretically possible.' (CVE-2023-25136)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Oracle Linux 9 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2023-2645 advisory.

    [8.7p1-29]
    - Resolve possible self-DoS with some clients       Resolves: rhbz#2186473

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

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

The remote AlmaLinux 9 host has packages installed that are affected by a vulnerability as referenced in the ALSA-2023:2645 advisory.

  - OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.
    This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in     the default configuration, to jump to any location in the sshd address space. One third-party report     states remote code execution is theoretically possible. (CVE-2023-25136)

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

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2023:2645 advisory.

    OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating     systems. It includes the core files necessary for both the OpenSSH client and server.

    Security Fix(es):

    * openssh: the functions order_hostkeyalgs() and list_hostkey_types() leads to double-free vulnerability     (CVE-2023-25136)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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

The remote Fedora 38 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2023-123647648e advisory.

    Avoid possible self-DoS attack     Resolves: CVE-2023-25136

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

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

The remote Fedora 37 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2023-1176c8b10c advisory.

    Avoid possible self-DoS attack     Resolves: CVE-2023-25136

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

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

The version of OpenSSH installed on the remote host is 9.1. It is, therefore, affected by a double-free vulnerability during options.kex_algorithms handling. The double free can be triggered by an unauthenticated attacker in the default configuration; however, the vulnerability discoverer reports that 'exploiting this vulnerability will not be easy.'

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

ID	Name	Product	Family	Severity
180347	FreeBSD : FreeBSD -- OpenSSH pre-authentication double free (09b7cd39-47bd-11ee-8e38-002590c1f29c)	Nessus	FreeBSD Local Security Checks	medium
179007	EulerOS Virtualization 2.10.0 : openssh (EulerOS-SA-2023-2479)	Nessus	Huawei Local Security Checks	medium
178992	EulerOS Virtualization 2.10.1 : openssh (EulerOS-SA-2023-2454)	Nessus	Huawei Local Security Checks	medium
178586	GLSA-202307-01 : OpenSSH: Remote Code Execution	Nessus	Gentoo Local Security Checks	critical
176039	EulerOS 2.0 SP10 : openssh (EulerOS-SA-2023-1981)	Nessus	Huawei Local Security Checks	medium
176008	EulerOS 2.0 SP10 : openssh (EulerOS-SA-2023-1959)	Nessus	Huawei Local Security Checks	medium
175995	Oracle Linux 9 : openssh (ELSA-2023-2645)	Nessus	Oracle Linux Local Security Checks	medium
175623	AlmaLinux 9 : openssh (ALSA-2023:2645)	Nessus	Alma Linux Local Security Checks	medium
175467	RHEL 9 : openssh (RHSA-2023:2645)	Nessus	Red Hat Local Security Checks	medium
174527	Fedora 38 : openssh (2023-123647648e)	Nessus	Fedora Local Security Checks	medium
174424	Fedora 37 : openssh (2023-1176c8b10c)	Nessus	Fedora Local Security Checks	medium
171133	OpenSSH 9.1 Double Free	Nessus	Misc.	medium

Detections

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CVE-2023-25136

medium

Tenable Plugins

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critical

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