CVE-2023-42116 HIGH

CVE-2023-42116: Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability

Vendor Exim
Product Exim
Weakness CWE-121
Published May 3, 2024
Last update November 4, 2025

CVSS base score

8.1/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

Exim SMTP Challenge Stack-based Buffer Overflow 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 handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.

Key dates

02Disclosure timeline

May 3, 2024 CVE published
November 4, 2025 Record updated