Detections
Analytics

OpenSSH < 10.3 Multiple Vulnerabilities

high Nessus Plugin ID 306743

Language:

Synopsis

The SSH server running on the remote host is affected by multiple vulnerabilities.

Description

The version of OpenSSH installed on the remote host is prior to 10.3. It is, therefore, affected by multiple vulnerabilities as referenced in the release-10.3 advisory.

 - In OpenSSH before 10.3, validation of shell metacharacters in user names supplied on the command-line was performed too late, allowing potential expansion from %-tokens in ssh_config. For configurations that use a %u token in a Match exec block, an attacker who can control the user name passed to ssh(1) could potentially execute arbitrary shell commands. (CVE-2026-35386)

 - In OpenSSH before 10.3, a file downloaded by scp may be installed setuid or setgid, an outcome contrary to some users' expectations, if the download is performed as root with -O (legacy scp protocol) and without -p (preserve mode). (CVE-2026-35385)

 - OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.
 (CVE-2026-35387)

 - In OpenSSH before 10.3, connection multiplexing confirmation (requested using ControlMaster ask/autoask) was not being tested for proxy mode multiplexing sessions (i.e. ssh -O proxy ...). (CVE-2026-35388)

 - OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters. (CVE-2026-35414)

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

Solution

Upgrade to OpenSSH version 10.3 or later.

See Also

https://www.openssh.com/txt/release-10.3

Plugin Details

Severity: High

ID: 306743

File Name: openssh_103.nasl

Version: 1.2

Type: Remote

Family: Misc.

Published: 4/16/2026

Updated: 4/17/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-35414

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.1

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:openbsd:openssh

Required KB Items: installed_sw/OpenSSH

Exploit Ease: No known exploits are available

Patch Publication Date: 4/2/2026

Vulnerability Publication Date: 4/2/2026

Reference Information

CVE: CVE-2026-35385, CVE-2026-35386, CVE-2026-35387, CVE-2026-35388, CVE-2026-35414

IAVA: 2026-A-0296