Linux Distros Unpatched Vulnerability : CVE-2026-27857

medium Nessus Plugin ID 304082

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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.

- Sending NOOP (((...))) command with 4000 parenthesis open+close results in ~1MB extra memory usage.
Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known. (CVE-2026-27857)

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: 304082

File Name: unpatched_CVE_2026_27857.nasl

Version: 1.5

Type: Local

Agent: unix

Family: Misc.

Published: 3/28/2026

Updated: 4/17/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 2.9

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.3

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

CVSS Score Source: CVE-2026-27857

CVSS v3

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 4

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:8, p-cpe:/a:canonical:ubuntu_linux:dovecot, cpe:/o:debian:debian_linux:11.0, p-cpe:/a:centos:centos:dovecot-pigeonhole, cpe:/o:centos:centos:7, p-cpe:/a:centos:centos:dovecot, p-cpe:/a:redhat:enterprise_linux:dovecot-pigeonhole, p-cpe:/a:centos:centos:dovecot-pgsql, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:dovecot, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:dovecot-devel, p-cpe:/a:redhat:enterprise_linux:dovecot-pgsql, p-cpe:/a:debian:debian_linux:dovecot, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:dovecot-devel, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:redhat:enterprise_linux:6, p-cpe:/a:centos:centos:dovecot-mysql, p-cpe:/a:redhat:enterprise_linux:dovecot-mysql

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-2026-27857

Detections

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