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Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Exim vulnerabilities (USN-8228-1)

critical Nessus Plugin ID 312296

Synopsis

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

Description

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8228-1 advisory.

 It was discovered that Exim incorrectly handled parsing malformed JSON in message headers. A remote attacker could possibly use this issue to execute arbitrary code. (CVE-2026-40685)

 It was discovered that Exim incorrectly handled processing of UTF-8 trailing characters. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-40686)

 It was discovered that Exim incorrectly handled SPA authenticator input. An authenticated user could possibly use this issue to execute arbitrary code. (CVE-2026-40687)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-8228-1

Plugin Details

Severity: Critical

ID: 312296

File Name: ubuntu_USN-8228-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 5/5/2026

Updated: 5/5/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-40685

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

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

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:exim4-dev, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:exim4-daemon-heavy, p-cpe:/a:canonical:ubuntu_linux:exim4-config, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:exim4, p-cpe:/a:canonical:ubuntu_linux:exim4-base, p-cpe:/a:canonical:ubuntu_linux:eximon4, p-cpe:/a:canonical:ubuntu_linux:exim4-daemon-light, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/4/2026

Vulnerability Publication Date: 4/30/2026

Reference Information

CVE: CVE-2026-40685, CVE-2026-40686, CVE-2026-40687

USN: 8228-1