CVE-2023-42117

Publication date 28 September 2023

Last updated 10 June 2026

Ubuntu priority

Cvss 3 Severity Score

Description

Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the smtp service, which listens on TCP port 25 by default. The issue results from the lack of proper validation of user-supplied data, which can result in a memory corruption condition. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-17554.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
exim4	23.10 mantic	Fixed 4.96-17ubuntu2.1
	23.04 lunar	Fixed 4.96-14ubuntu1.3
	22.04 LTS jammy	Fixed 4.95-4ubuntu2.4
	20.04 LTS focal	Fixed 4.93-13ubuntu1.9
	18.04 LTS bionic	Fixed 4.90.1-1ubuntu1.10+esm2
	16.04 LTS xenial	Fixed 4.86.2-2ubuntu2.6+esm5
	14.04 LTS trusty	Fixed 4.82-3ubuntu2.4+esm7

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Notes

allenpthuang

fixes published, see ZDI's note.

mdeslaur

The original update introduced a regression, see LP bug.

Severity score breakdown

CVSS version: CVSS v3.0

Base score 8.1 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	8.1 · High
Exploitability score	-
Impact score	-