CentOS Linux 6 [TuxCare] Security Update: libssh2 / libssh2-devel / libssh2-docs Multiple Vulnerabilities (CENTOS6:CLSA-2026:1778159627)

high Nessus Plugin ID 351965

Synopsis

The CentOS Linux host is missing one or more security updates.

Description

The CentOS Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare CENTOS6:CLSA-2026:1778159627 advisory.

- In libssh2 before 1.9.0, kex_method_diffie_hellman_group_exchange_sha256_key_exchange in kex.c has an integer overflow that could lead to an out-of-bounds read in the way packets are read from the server. A remote attacker who compromises a SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server. This is related to an
_libssh2_check_length mistake, and is different from the various issues fixed in 1.8.1, such as CVE-2019-3855. (CVE-2019-13115)

- In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds check, enabling an attacker to specify an arbitrary (out-of-bounds) offset for a subsequent memory read. A crafted SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server. (CVE-2019-17498)

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 packages based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1778159627.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1778159627

http://www.nessus.org/u?3048a7aa

Plugin Details

Severity: High

ID: 351965

File Name: tuxcare_centos_6_CLSA-2026-1778159627.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 9/30/2026

Updated: 9/30/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.3

Percentile: 96.95

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.5

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

CVSS Score Source: CVE-2019-17498

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.3

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

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

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/CentOS/release, Host/CentOS/rpm-list, Host/OS/extended-third-party

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/7/2026

Vulnerability Publication Date: 7/16/2019

Reference Information

CVE: CVE-2019-13115, CVE-2019-17498

CLSA: 2026:1778159627