What is CVE-2023-42118?

CVE-2023-42118 is a high-severity vulnerability in Exim, classified under Integer Underflow. CVSS score: 8.8/10. Published 2024-05-03.

How severe is CVE-2023-42118?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2023-42118 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Integer overflow in Exim

CVE-2023-42118

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.

EPSS: 0.518 (98.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Exim
Exim Libspf2 — versions exim 4.96-RC0-14-24b8ed847-XX
Libspf2_project Libspf2

Weakness classification (CWE)

CWE-191 — Integer Underflow

Public proof-of-concept exploits

References

zdi-disclosures@trendmicro.com (x_research-advisory, Third Party Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List)

Frequently asked questions

What is CVE-2023-42118?: CVE-2023-42118 is a high-severity vulnerability in Exim, classified under Integer Underflow. CVSS score: 8.8/10. Published 2024-05-03.
How severe is CVE-2023-42118?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2023-42118 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.