CVE-2023-42116: exim Stack-based Buffer Overflow

Vulnerability summary

CVE-2023-42116 is a critical (CVSS 9.8) Stack-based Buffer Overflow vulnerability in exim. EPSS estimates a 3.76% chance of exploitation in the next 30 days, higher than 89.7% of scored vulnerabilities.

Timeline

1. 03-05-2024
   PublishedVulnerability first disclosed.
2. 04-11-2025
   Last modifiedVulnerability information updated.

Description

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.

• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).