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CVE-2023-42118

55
FAUCET Score

CVE-2023-42118 is a critical remote code execution vulnerability affecting Exim mail servers utilizing libspf2, specifically within the parsing of SPF macros. This flaw allows unauthenticated, network-adjacent attackers to execute arbitrary code due to an integer underflow when processing user-supplied data. With a CVSS score of 8.8 (High), exploitation requires low attack complexity and can lead to complete compromise of confidentiality, integrity, and availability. While not currently listed on the KEV catalog, its high media coverage and community discussion indicate significant attention, though no public exploit code is yet available.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:libspf2_project:libspf2:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

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

Attack Vector
ADJACENT_NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.6
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
51.47%
Probability of exploitation in next 30 days
EPSS Percentile
98.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.5147 is in the 99th percentile among its peer group of 1,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.2 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2023-42118Important

libspf2: Integer Underflow Remote Code Execution Vulnerability

Sep 27, 2023

References

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