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Debian dla-4844 : libssh-4 - security update

medium Nessus Plugin ID 372635

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4844 advisory.

 - ------------------------------------------------------------------------- Debian LTS Advisory DLA-4844-1 [email protected] https://www.debian.org/lts/security/ Simon Quigley October 20, 2026 https://wiki.debian.org/LTS
 - -------------------------------------------------------------------------

 Package : libssh Version : 0.10.6-0+deb12u3 CVE ID : CVE-2026-0964 CVE-2026-0965 CVE-2026-0966 CVE-2026-0967 CVE-2026-0968 CVE-2026-3731 CVE-2026-59843 CVE-2026-59844 CVE-2026-59845 CVE-2026-59846 CVE-2026-59847 CVE-2026-59848 CVE-2026-59850

 Several vulnerabilities were discovered in libssh, a tiny C SSH library.

 CVE-2026-0964

 A malicious SCP server can send a path that escapes the working directory. This is the same issue as OpenSSH CVE-2019-6111.

 CVE-2026-0965

 Parsing a configuration file that is not a regular file, or that is too large, could be used for a denial of service.

 CVE-2026-0966

 ssh_get_hexa() could underflow a heap buffer on invalid input.

 CVE-2026-0967

 A crafted pattern in a configuration or known_hosts file could make match_pattern() backtrack until it times out.

 CVE-2026-0968

 A malicious SFTP server can send a longname that sftp_parse_longname() reads past.

 CVE-2026-3731

 sftp_extensions_get_name() and sftp_extensions_get_data() did not reject an index past the end of the extension list.

 CVE-2026-59843

 A peer that advertises a maximum channel packet size of 0 can cause a denial of service.

 CVE-2026-59844

 An oversized length in an SSH_FXP_READ request can cause a denial of service.

 CVE-2026-59845

 ProxyCommand did not check the return value of fork(), which can cause a denial of service.

 CVE-2026-59846

 A username containing shell metacharacters could be expanded into ProxyCommand via %r.

 CVE-2026-59847

 With the OpenSSL backend, a failed AES-GCM tag check could be treated as success. The gcrypt backend was already correct.

 CVE-2026-59848

 An SFTP response with a request id the client did not send could cause a denial of service.

 CVE-2026-59850

 A DATA packet on a remotely closed channel could be delivered to a callback after the channel was freed.

 For Debian 12 bookworm, these problems have been fixed in version 0.10.6-0+deb12u3.

 We recommend that you upgrade your libssh packages.

 For the detailed security status of libssh please refer to its security tracker page at:
 https://security-tracker.debian.org/tracker/libssh

 Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the libssh-4 packages.

See Also

https://packages.debian.org/source/bookworm/libssh

https://security-tracker.debian.org/tracker/CVE-2019-6111

https://security-tracker.debian.org/tracker/CVE-2026-0964

https://security-tracker.debian.org/tracker/CVE-2026-0965

https://security-tracker.debian.org/tracker/CVE-2026-0966

https://security-tracker.debian.org/tracker/CVE-2026-0967

https://security-tracker.debian.org/tracker/CVE-2026-0968

https://security-tracker.debian.org/tracker/CVE-2026-3731

https://security-tracker.debian.org/tracker/CVE-2026-59843

https://security-tracker.debian.org/tracker/CVE-2026-59844

https://security-tracker.debian.org/tracker/CVE-2026-59845

https://security-tracker.debian.org/tracker/CVE-2026-59846

https://security-tracker.debian.org/tracker/CVE-2026-59847

https://security-tracker.debian.org/tracker/CVE-2026-59848

https://security-tracker.debian.org/tracker/CVE-2026-59850

https://security-tracker.debian.org/tracker/source-package/libssh

Plugin Details

Severity: Medium

ID: 372635

File Name: debian_DLA-4844.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 10/27/2026

Updated: 10/27/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.7

Percentile: 96.29

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2026-3731

CVSS v3

Risk Factor: High

Base Score: 8.2

Temporal Score: 7.1

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

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

CVSS Score Source: CVE-2026-0966

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:libssh-4, p-cpe:/a:debian:debian_linux:libssh-dev, p-cpe:/a:debian:debian_linux:libssh-doc, p-cpe:/a:debian:debian_linux:libssh-gcrypt-4, p-cpe:/a:debian:debian_linux:libssh-gcrypt-dev

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 10/20/2026

Vulnerability Publication Date: 2/19/2026

Reference Information

CVE: CVE-2019-6111, CVE-2026-0964, CVE-2026-0965, CVE-2026-0966, CVE-2026-0967, CVE-2026-0968, CVE-2026-3731, CVE-2026-59843, CVE-2026-59844, CVE-2026-59845, CVE-2026-59846, CVE-2026-59847, CVE-2026-59848, CVE-2026-59850