AlmaLinux 9 : libssh (ALSA-2026:62217)

high Nessus Plugin ID 342447

Synopsis

The remote AlmaLinux host is missing one or more security updates.

Description

The remote AlmaLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:62217 advisory.

* 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)

Tenable has extracted the preceding description block directly from the AlmaLinux 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 affected libssh, libssh-config and / or libssh-devel packages.

See Also

https://access.redhat.com/errata/RHSA-2026:62217

https://errata.almalinux.org/9/ALSA-2026-62217.html

Plugin Details

Severity: High

ID: 342447

File Name: alma_linux_ALSA-2026-62217.nasl

Version: 1.1

Type: Local

Published: 9/2/2026

Updated: 9/2/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

Percentile: 51.06

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:alma:linux:9, cpe:/o:alma:linux:9::appstream, cpe:/o:alma:linux:9::baseos, cpe:/o:alma:linux:9::crb, cpe:/o:alma:linux:9::highavailability, cpe:/o:alma:linux:9::nfv, cpe:/o:alma:linux:9::realtime, cpe:/o:alma:linux:9::resilientstorage, cpe:/o:alma:linux:9::sap, cpe:/o:alma:linux:9::sap_hana, cpe:/o:alma:linux:9::supplementary, p-cpe:/a:alma:linux:libssh-config, p-cpe:/a:alma:linux:libssh-devel, p-cpe:/a:alma:linux:libssh

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

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