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CVE-2023-42116

Exim remote code execution

9.8 CRITICALEPSS 3.76%
  1. Published3 May 2024

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Exim< 4.96.1

Remediation

Fixed in
Exim≥ 4.96.1

References

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Frequently asked

Is CVE-2023-42116 being actively exploited?

CVE-2023-42116 is not in the CISA KEV catalog. Its EPSS exploit probability is 3.76%.

How severe is CVE-2023-42116?

CVE-2023-42116 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 3.76% probability of exploitation.

Which products are affected by CVE-2023-42116?

Affected products include Exim.

How do I fix CVE-2023-42116?

Upgrade affected software to a fixed version, for example Exim 4.96.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2023-42116 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.