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Debian dla-4617 : dovecot-auth-lua - security update

medium Nessus Plugin ID 318856

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4617 advisory.

 ------------------------------------------------------------------------- Debian LTS Advisory DLA-4617-1 [email protected] https://www.debian.org/lts/security/ Guilhem Moulin June 05, 2026 https://wiki.debian.org/LTS
 -------------------------------------------------------------------------

 Package : dovecot Version : 1:2.3.13+dfsg1-2+deb11u4 CVE ID : CVE-2026-33603 CVE-2026-40020 CVE-2026-42006 Debian Bug : 1136444

 Multiple vulnerabilities were discovered in dovecot, a POP3/IMAP server, which could lead to Denial of Service or information leak.

 CVE-2026-33603

 An attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding and later eavesdrop communications between Dovecot and client as MITM proxy.

 CVE-2026-40020

 An attacker can use the IMAP `SETACL` command to inject the anyone permission to user's dovecot-acl file even if `imap_acl_allow_anyone=no`, thereby allowing folders to be spammed to all users. (The impact was limited to being able to spam folders to other users. No unexpected access is gained.)

 CVE-2026-42006

 An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. This stems from an incomplete fix for CVE-2026-27857.

 For Debian 11 bullseye, these problems have been fixed in version 1:2.3.13+dfsg1-2+deb11u4.

 We recommend that you upgrade your dovecot packages.

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

 Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS Attachment:
 signature.asc Description: PGP signature

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the dovecot-auth-lua packages.

See Also

https://security-tracker.debian.org/tracker/source-package/dovecot

https://security-tracker.debian.org/tracker/CVE-2026-27857

https://security-tracker.debian.org/tracker/CVE-2026-33603

https://security-tracker.debian.org/tracker/CVE-2026-40020

https://security-tracker.debian.org/tracker/CVE-2026-42006

https://packages.debian.org/source/bullseye/dovecot

Plugin Details

Severity: Medium

ID: 318856

File Name: debian_DLA-4617.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 6/5/2026

Updated: 6/5/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2026-33603

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, p-cpe:/a:debian:debian_linux:dovecot-lmtpd, p-cpe:/a:debian:debian_linux:dovecot-pgsql, p-cpe:/a:debian:debian_linux:dovecot-sqlite, p-cpe:/a:debian:debian_linux:dovecot-pop3d, p-cpe:/a:debian:debian_linux:dovecot-gssapi, p-cpe:/a:debian:debian_linux:dovecot-lucene, p-cpe:/a:debian:debian_linux:dovecot-managesieved, p-cpe:/a:debian:debian_linux:dovecot-submissiond, p-cpe:/a:debian:debian_linux:dovecot-sieve, p-cpe:/a:debian:debian_linux:dovecot-dev, p-cpe:/a:debian:debian_linux:dovecot-core, p-cpe:/a:debian:debian_linux:dovecot-auth-lua, p-cpe:/a:debian:debian_linux:dovecot-ldap, p-cpe:/a:debian:debian_linux:dovecot-mysql, p-cpe:/a:debian:debian_linux:dovecot-imapd, p-cpe:/a:debian:debian_linux:dovecot-solr

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

Exploit Ease: No known exploits are available

Patch Publication Date: 6/5/2026

Vulnerability Publication Date: 3/27/2026

Reference Information

CVE: CVE-2026-27857, CVE-2026-33603, CVE-2026-40020, CVE-2026-42006