Detections
Analytics
Linux Distros Unpatched Vulnerability : CVE-2026-55200
critical Nessus Plugin ID 321726
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Synopsis
The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.Description
The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.- libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution. (CVE-2026-55200)
Note that Nessus relies on the presence of the package as reported by the vendor.
Solution
There is no known solution at this time.See Also
https://access.redhat.com/security/cve/cve-2026-55200
Plugin Details
Severity: Critical
ID: 321726
File Name: unpatched_CVE_2026_55200.nasl
Version: 1.6
Type: Local
Agent: unix
Family: Misc.
Published: 6/20/2026
Updated: 7/10/2026
Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: High
Score: 8.5
Percentile: 99.7
CVSS v2
Risk Factor: High
Base Score: 9.7
Temporal Score: 8.7
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:P
CVSS Score Source: CVE-2026-55200
CVSS v3
Risk Factor: High
Base Score: 8.3
Temporal Score: 7.9
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
Temporal Vector: CVSS:3.0/E:P/RL:U/RC:C
CVSS v4
Risk Factor: Critical
Base Score: 9.2
Threat Score: 7.2
Threat Vector: CVSS:4.0/E:P
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Vulnerability Information
CPE: p-cpe:/a:redhat:enterprise_linux:libssh2, cpe:/o:centos:centos:7, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:debian:debian_linux:libssh2, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:redhat:enterprise_linux:libssh2-devel, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:redhat:enterprise_linux:libssh2-docs, p-cpe:/a:canonical:ubuntu_linux:libssh2, p-cpe:/a:centos:centos:libssh2-docs, p-cpe:/a:centos:centos:libssh2-devel, p-cpe:/a:centos:centos:libssh2, cpe:/o:debian:debian_linux:12.0
Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier
Exploit Available: true
Exploit Ease: Exploits are available
Vulnerability Publication Date: 6/17/2026
Reference Information
CVE: CVE-2026-55200