RHEL 9 : krb5 (RHSA-2026:24686)

medium Nessus Plugin ID 320013

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Synopsis

The remote Red Hat host is missing a security update for krb5.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2026:24686 advisory.

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es):

* krb5: MIT Kerberos 5 (krb5): Denial of Service via integer underflow and out-of-bounds read (CVE-2026-40356)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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 RHEL krb5 package based on the guidance in RHSA-2026:24686.

Plugin Details

Severity: Medium

ID: 320013

File Name: redhat-RHSA-2026-24686.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 6/9/2026

Updated: 6/9/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4

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

CVSS Score Source: CVE-2026-40356

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

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

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

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:libkadm5, cpe:/o:redhat:rhel_e4s:9.4, p-cpe:/a:redhat:enterprise_linux:krb5-server-ldap, p-cpe:/a:redhat:enterprise_linux:krb5-pkinit, p-cpe:/a:redhat:enterprise_linux:krb5, p-cpe:/a:redhat:enterprise_linux:krb5-server, p-cpe:/a:redhat:enterprise_linux:krb5-workstation, p-cpe:/a:redhat:enterprise_linux:krb5-libs, p-cpe:/a:redhat:enterprise_linux:krb5-devel

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 6/9/2026

Vulnerability Publication Date: 4/28/2026

Reference Information

CVE: CVE-2026-40356

CWE: 191

RHSA: 2026:24686

Detections

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