CVE-2023-42118

Name: CVE-2023-42118
Creator: NVD / NIST
Published: 2024-05-03T03:15:50.643+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 51.47%

Last modified Jun 17, 2026

CVE-2023-42118 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Exim libspf2 Integer Underflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Exim libspf2. EPSS estimates a 51.47% chance of exploitation in the next 30 days.

Description

Exim libspf2 Integer Underflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Exim libspf2. Authentication is not required to exploit this vulnerability. The specific flaw exists within the parsing of SPF macros. When parsing SPF macros, the process does not properly validate user-supplied data, which can result in an integer underflow before writing to memory. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17578.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

51.47%

98.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-191

Affected Software

Vendor	Product	Versions
Libspf2 Project	Libspf2	All versions

References

https://www.zerodayinitiative.com/advisories/ZDI-23-1472/Third Party Advisory
http://www.openwall.com/lists/oss-security/2025/03/28/1Mailing List
https://www.zerodayinitiative.com/advisories/ZDI-23-1472/Third Party Advisory

Timeline

Published: May 3, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2023-42118?

How severe is CVE-2023-42118?

CVE-2023-42118 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 51.47% probability of exploitation in the next 30 days.

How do I fix CVE-2023-42118?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-42118?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST