Debian dsa-6293 : krb5-admin-server - security update

medium Nessus Plugin ID 316549

Synopsis

The remote Debian host is missing a security-related update.

Description

The remote Debian 12 / 13 host has packages installed that are affected by a vulnerability as referenced in the dsa-6293 advisory.

- ------------------------------------------------------------------------- Debian Security Advisory DSA-6293-1 [email protected] https://www.debian.org/security/ Salvatore Bonaccorso May 22, 2026 https://www.debian.org/security/faq
- -------------------------------------------------------------------------

Package : krb5 CVE ID : CVE-2026-40355 Debian Bug : 1135317

Cem Onat Karagun discovered two vulnerabilities in the NegoEx parsing in krb5, the MIT implementation of Kerberos. An unauthenticated remote attacker can take advantage of these flaws to cause a denial of service.

For the oldstable distribution (bookworm), this problem has been fixed in version 1.20.1-2+deb12u5.

For the stable distribution (trixie), this problem has been fixed in version 1.21.3-5+deb13u1.

We recommend that you upgrade your krb5 packages.

For the detailed security status of krb5 please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/krb5

Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: https://www.debian.org/security/

Mailing list: [email protected]

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the krb5-admin-server packages.

Plugin Details

Severity: Medium

ID: 316549

File Name: debian_DSA-6293.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 5/25/2026

Updated: 5/25/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

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-2026-40355

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:debian:debian_linux:krb5-pkinit, p-cpe:/a:debian:debian_linux:libkrb5support0, p-cpe:/a:debian:debian_linux:krb5-gss-samples, p-cpe:/a:debian:debian_linux:libkrad0, p-cpe:/a:debian:debian_linux:libgssrpc4t64, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:debian:debian_linux:libkadm5clnt-mit12, p-cpe:/a:debian:debian_linux:libkrad-dev, p-cpe:/a:debian:debian_linux:krb5-kdc, p-cpe:/a:debian:debian_linux:krb5-otp, p-cpe:/a:debian:debian_linux:krb5-admin-server, p-cpe:/a:debian:debian_linux:libgssapi-krb5-2, p-cpe:/a:debian:debian_linux:libkrb5-dev, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:debian:debian_linux:libkdb5-10t64, p-cpe:/a:debian:debian_linux:libkdb5-10, p-cpe:/a:debian:debian_linux:krb5-multidev, p-cpe:/a:debian:debian_linux:libgssrpc4, p-cpe:/a:debian:debian_linux:libk5crypto3, p-cpe:/a:debian:debian_linux:libkrb5-dbg, p-cpe:/a:debian:debian_linux:krb5-locales, p-cpe:/a:debian:debian_linux:krb5-user, p-cpe:/a:debian:debian_linux:libkadm5srv-mit12, p-cpe:/a:debian:debian_linux:libkrb5-3, p-cpe:/a:debian:debian_linux:krb5-kpropd, p-cpe:/a:debian:debian_linux:krb5-doc, p-cpe:/a:debian:debian_linux:krb5-k5tls, p-cpe:/a:debian:debian_linux:krb5-kdc-ldap

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/22/2026

Vulnerability Publication Date: 4/28/2026

Reference Information

CVE: CVE-2026-40355

Detections

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