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Fencer Vulns
high 7.5

CVE-2023-42118 json

Exim libspf2 Integer Underflow Remote Code Execution Vulnerability

published 2024-05-03 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-46577

cvss
7.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
8.4%
EPSS 8.4% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

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.

Patch / fix

  • libspf2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 1.2.11-r3

alpine advisories ALPINE-CVE-2023-42118

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-42118 updated cvss 7.5

libspf2: Integer Underflow Remote Code Execution Vulnerability

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

8.35% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 7.5 CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Exim libspf2

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.