RHEL 9 : libssh (RHSA-2026:62217)

high Nessus Plugin ID 342247

Synopsis

The remote Red Hat host is missing one or more security updates for libssh.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:62217 advisory.

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.

Security Fix(es):

* libssh: libssh: denial of service via zero advertised channel packet size (CVE-2026-59843)

* libssh: libssh: denial of service via oversized SFTP read length (CVE-2026-59844)

* libssh: libssh: denial of service via unchecked ProxyCommand fork() failure (CVE-2026-59845)

* libssh: libssh: information disclosure via ProxyCommand %r username expansion (CVE-2026-59846)

* libssh: libssh: integrity downgrade via OpenSSL AES-GCM tag verification (CVE-2026-59847)

* libssh: libssh: denial of service via SFTP responses with unknown request IDs (CVE-2026-59848)

* libssh: libssh: use-after-free via data callbacks on closed channels (CVE-2026-59850)

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 these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL libssh package based on the guidance in RHSA-2026:62217.

Plugin Details

Severity: High

ID: 342247

File Name: redhat-RHSA-2026-62217.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 9/1/2026

Updated: 9/1/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

Percentile: 51.06

Vendor

Vendor Severity: Moderate

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-59847

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:9, cpe:/o:redhat:rhel_eus:9.8, p-cpe:/a:redhat:enterprise_linux:libssh-config, p-cpe:/a:redhat:enterprise_linux:libssh-devel, p-cpe:/a:redhat:enterprise_linux:libssh

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 9/1/2026

Vulnerability Publication Date: 7/21/2026

Reference Information

CVE: CVE-2026-59843, CVE-2026-59844, CVE-2026-59845, CVE-2026-59846, CVE-2026-59847, CVE-2026-59848, CVE-2026-59850

CWE: 253, 390, 416, 770, 78, 789, 835

RHSA: 2026:62217

Detections

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