Detections
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Linux Distros Unpatched Vulnerability : CVE-2026-40356

high Nessus Plugin ID 310774

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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.

 - In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message. (CVE-2026-40356)

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-2026-40356

https://ubuntu.com/security/CVE-2026-40356

Plugin Details

Severity: High

ID: 310774

File Name: unpatched_CVE_2026_40356.nasl

Version: 1.10

Type: Local

Agent: unix

Family: Misc.

Published: 4/29/2026

Updated: 8/5/2026

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: Low

Score: 3

Percentile: 23.75

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.5

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

CVSS Score Source: CVE-2026-40356

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 7.1

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:6, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:canonical:ubuntu_linux:krb5, p-cpe:/a:centos:centos:krb5-devel, p-cpe:/a:centos:centos:krb5-libs, p-cpe:/a:centos:centos:krb5-pkinit-openssl, p-cpe:/a:centos:centos:krb5-pkinit, p-cpe:/a:centos:centos:krb5-server-ldap, p-cpe:/a:centos:centos:krb5-server, p-cpe:/a:centos:centos:krb5-workstation, p-cpe:/a:centos:centos:krb5, p-cpe:/a:centos:centos:libkadm5, p-cpe:/a:redhat:enterprise_linux:krb5-devel, p-cpe:/a:redhat:enterprise_linux:krb5-libs, p-cpe:/a:redhat:enterprise_linux:krb5-pkinit-openssl, p-cpe:/a:redhat:enterprise_linux:krb5-pkinit, p-cpe:/a:redhat:enterprise_linux:krb5-server-ldap, p-cpe:/a:redhat:enterprise_linux:krb5-server, p-cpe:/a:redhat:enterprise_linux:krb5-workstation, p-cpe:/a:redhat:enterprise_linux:krb5, p-cpe:/a:redhat:enterprise_linux:libkadm5

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 4/28/2026

Reference Information

CVE: CVE-2026-40356