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CentOS Linux 6 [TuxCare] Security Update: libssh2 / libssh2-devel / libssh2-docs (CENTOS6:CLSA-2026:1787063936)

high Nessus Plugin ID 351718

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 a vulnerability as referenced in the TuxCare CENTOS6:CLSA-2026:1787063936 advisory.

 - libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.
 (CVE-2026-66032)

Note that Nessus has not tested for this issue 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-2026:1787063936.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1787063936

http://www.nessus.org/u?975ee395

Plugin Details

Severity: High

ID: 351718

File Name: tuxcare_centos_6_CLSA-2026-1787063936.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: 6.9

Percentile: 96.51

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-66032

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

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

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

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.3

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

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

Exploit Ease: No known exploits are available

Patch Publication Date: 8/18/2026

Vulnerability Publication Date: 7/24/2026

Reference Information

CVE: CVE-2026-66032

CLSA: 2026:1787063936