Detections
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Ubuntu 24.04 LTS / 26.04 LTS / Pro Realtime 24.04 LTS : libssh2 vulnerabilities (USN-8722-1)

high Nessus Plugin ID 344609

Synopsis

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

Description

The remote Ubuntu 24.04 LTS / 26.04 LTS / Pro Realtime 24.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8722-1 advisory.

 It was discovered that libssh2 incorrectly handled certain SFTP server responses. A remote attacker controlling an SSH server could use this issue to cause libssh2 to crash or possibly execute arbitrary code. (CVE-2026-66032)

 It was discovered that libssh2 incorrectly handled AES-GCM cipher negotiation. A remote attacker controlling an SSH server could possibly use this issue to cause libssh2 to crash, resulting in a denial of service. (CVE-2026-66033)

 It was discovered that libssh2 incorrectly handled Encrypt-then-MAC cipher negotiation. A remote attacker controlling an SSH server could use this issue to cause libssh2 to crash or possibly execute arbitrary code. (CVE-2026-66035)

Tenable has extracted the preceding description block directly from the Ubuntu 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 libssh2-1t64 package.

See Also

https://ubuntu.com/security/notices/USN-8722-1

Plugin Details

Severity: High

ID: 344609

File Name: ubuntu_USN-8722-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 9/10/2026

Updated: 9/10/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.6

Percentile: 98.37

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: 6.6

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:H/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2026-66033

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:canonical:ubuntu_linux:pro:-:lts, p-cpe:/a:canonical:ubuntu_linux:libssh2-1t64

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/3/2026

Vulnerability Publication Date: 7/24/2026

Reference Information

CVE: CVE-2026-66032, CVE-2026-66033, CVE-2026-66035

USN: 8722-1