Linux Distros Unpatched Vulnerability : CVE-2026-27855

medium Nessus Plugin ID 304111

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.

- Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.
(CVE-2026-27855)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 304111

File Name: unpatched_CVE_2026_27855.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 3/28/2026

Updated: 3/28/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.7

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.4

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

CVSS Score Source: CVE-2026-27855

CVSS v3

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 6.2

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:dovecot, p-cpe:/a:centos:centos:dovecot-devel, p-cpe:/a:centos:centos:dovecot-mysql, p-cpe:/a:centos:centos:dovecot-pgsql, p-cpe:/a:centos:centos:dovecot-pigeonhole, p-cpe:/a:debian:debian_linux:dovecot, p-cpe:/a:redhat:enterprise_linux:dovecot, p-cpe:/a:redhat:enterprise_linux:dovecot-devel, p-cpe:/a:redhat:enterprise_linux:dovecot-mysql, p-cpe:/a:redhat:enterprise_linux:dovecot-pgsql, p-cpe:/a:redhat:enterprise_linux:dovecot-pigeonhole, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, cpe:/o:debian:debian_linux:14.0

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 3/27/2026

Reference Information

CVE: CVE-2026-27855

Detections

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