Is CVE-2023-42116 in the CISA KEV catalog?

No. CVE-2023-42116 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2023-42116?

CVE-2023-42116 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2023-42116?

CVE-2023-42116 has an EPSS score of 3.16% (86th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2023-42116?

Upgrade exim4 on debian 11 to 4.94.2-7+deb11u1 or later. Fixes are available for 6 affected products.

CVE & CISA-KEV Catalog

CVE-2023-42116

CRITICALEPSS 86th pctl

9.8

CVSS v3

NVD

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 Overflow

How to fix

Remediation Available

exim4Debian

Fixed in:4.94.2-7+deb11u1CVE-2023-42116

Fixed in:4.96-15+deb12u2CVE-2023-42116

Fixed in:4.97~RC1-2CVE-2023-42116

exim4Ubuntu

Fixed in:4.82-3ubuntu2.4+esm6USN-6411-1

Fixed in:4.86.2-2ubuntu2.6+esm4USN-6411-1

Fixed in:4.90.1-1ubuntu1.10+esm1USN-6411-1

Fixed in:4.93-13ubuntu1.8USN-6411-1

Fixed in:4.95-4ubuntu2.3USN-6411-1

Fixed in:4.96-14ubuntu1.2USN-6411-1

exim4-baseUbuntu

Fixed in:4.82-3ubuntu2.4+esm6USN-6411-1

Fixed in:4.86.2-2ubuntu2.6+esm4USN-6411-1

Fixed in:4.90.1-1ubuntu1.10+esm1USN-6411-1

Fixed in:4.93-13ubuntu1.8USN-6411-1

Fixed in:4.95-4ubuntu2.3USN-6411-1

Fixed in:4.96-14ubuntu1.2USN-6411-1

exim4-daemon-heavyUbuntu

Fixed in:4.82-3ubuntu2.4+esm6USN-6411-1

Fixed in:4.86.2-2ubuntu2.6+esm4USN-6411-1

Fixed in:4.90.1-1ubuntu1.10+esm1USN-6411-1

Fixed in:4.93-13ubuntu1.8USN-6411-1

Fixed in:4.95-4ubuntu2.3USN-6411-1

Fixed in:4.96-14ubuntu1.2USN-6411-1

exim4-daemon-lightUbuntu

Fixed in:4.82-3ubuntu2.4+esm6USN-6411-1

Fixed in:4.86.2-2ubuntu2.6+esm4USN-6411-1

Fixed in:4.90.1-1ubuntu1.10+esm1USN-6411-1

Fixed in:4.93-13ubuntu1.8USN-6411-1

Fixed in:4.95-4ubuntu2.3USN-6411-1

Fixed in:4.96-14ubuntu1.2USN-6411-1

eximon4Ubuntu

Fixed in:4.82-3ubuntu2.4+esm6USN-6411-1

Fixed in:4.86.2-2ubuntu2.6+esm4USN-6411-1

Fixed in:4.90.1-1ubuntu1.10+esm1USN-6411-1

Fixed in:4.93-13ubuntu1.8USN-6411-1

Fixed in:4.95-4ubuntu2.3USN-6411-1

Fixed in:4.96-14ubuntu1.2USN-6411-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

3.16%probability of exploitation in 30 days

86thpercentile

Elevated risk: more likely to be exploited than 86% of all known CVEs.

References

Third-Party Advisory1

zerodayinitiative.com

Other references1

lists.debian.org

Related Vulnerabilities

Other CWE-121 (Stack-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2009-0927	High	8.8	97%	KEV	Fix
CVE-2020-10924	High	8.8	87%	-	-
CVE-2022-20705	Critical	10.0	80%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.