AlmaLinux 8 : dovecot (ALSA-2026:76763)

critical Nessus Plugin ID 363927

Synopsis

The remote AlmaLinux host is missing one or more security updates.

Description

The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:76763 advisory.

* dovecot: Dovecot: Denial of Service via IMAP ID command with excessive parameters (CVE-2026-42391)
* dovecot: Dovecot: Authentication bypass via incorrect OAuth2 token validation (CVE-2026-73208)
* dovecot: Dovecot: Denial of service via crafted email headers (CVE-2026-27852)
* dovecot: Dovecot: Denial of Service via truncated quoted argument in ManageSieve (CVE-2026-40019)
* dovecot: Dovecot: Denial of Service and potential message duplication via connection limit exhaustion (CVE-2026-33263)
* dovecot: Dovecot: Denial of Service in ManageSieve login process (CVE-2026-33605)
* dovecot: Dovecot: Arbitrary Code Execution via Sieve editheader use-after-free (CVE-2026-42007)
* dovecot: Dovecot: MySQL multi-byte escaping wrong (CVE-2026-40018)


Bug Fix(es) and Enhancement(s):

* Dovecot crashes when accessing mailbox with: Panic: file mail-user.c: line 229 (mail_user_deinit):
assertion failed: ((*user)->refcount == 1) (JIRA:AlmaLinux-176273)

Tenable has extracted the preceding description block directly from the AlmaLinux 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

Update the affected packages.

See Also

https://access.redhat.com/errata/RHSA-2026:76763

https://errata.almalinux.org/8/ALSA-2026-76763.html

Plugin Details

Severity: Critical

ID: 363927

File Name: alma_linux_ALSA-2026-76763.nasl

Version: 1.1

Type: Local

Published: 10/7/2026

Updated: 10/7/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

Percentile: 57.58

CVSS v2

Risk Factor: High

Base Score: 8

Temporal Score: 5.9

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

CVSS Score Source: CVE-2026-42007

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

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

Vulnerability Information

CPE: cpe:/o:alma:linux:8, cpe:/o:alma:linux:8::appstream, cpe:/o:alma:linux:8::baseos, cpe:/o:alma:linux:8::highavailability, cpe:/o:alma:linux:8::nfv, cpe:/o:alma:linux:8::powertools, cpe:/o:alma:linux:8::realtime, cpe:/o:alma:linux:8::resilientstorage, cpe:/o:alma:linux:8::sap, cpe:/o:alma:linux:8::sap_hana, cpe:/o:alma:linux:8::supplementary, p-cpe:/a:alma:linux:dovecot-devel, p-cpe:/a:alma:linux:dovecot-mysql, p-cpe:/a:alma:linux:dovecot-pgsql, p-cpe:/a:alma:linux:dovecot-pigeonhole, p-cpe:/a:alma:linux:dovecot

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/6/2026

Vulnerability Publication Date: 8/28/2026

Reference Information

CVE: CVE-2026-27852, CVE-2026-33263, CVE-2026-33605, CVE-2026-40018, CVE-2026-40019, CVE-2026-42007, CVE-2026-42391, CVE-2026-73208

CWE: 1286, 303, 770, 825, 835, 89, 910

RHSA: 2026:76763