CVE-2023-42119

Network-adjacent information disclosure via crafted DNS responses

Published May 3, 2024 · Updated Nov 3, 2025

Out-of-bounds read in Exim before 4.96.2 allows network-adjacent attackers to disclose process memory through crafted DNS responses. The dnsdb DNS-record parser fails to validate returned record lengths before copying fields, so a malformed response drives a read beyond the allocated reply buffer. No authentication is required, but the attacker must influence DNS replies received by the SMTP service; the flaw discloses data and does not independently execute code.

CVSS severity3.1
Low
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Exim before 4.96.2 allows network-adjacent attackers to disclose process memory through crafted DNS responses. The dnsdb DNS-record parser fails to validate returned record lengths before copying fields, so a malformed response drives a read beyond the allocated reply buffer. No authentication is required, but the attacker must influence DNS replies received by the SMTP service; the flaw discloses data and does not independently execute code.

The record

CVE
CVE-2023-42119
Published
May 3, 2024
Updated
Nov 3, 2025
Vendor
LibSPF2 Project
Product
Exim
Classifications
CWE-125, T1190
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=exim 4.96-RC0-14-24b8ed847-XX

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

LibSPF2 Project · Eximversion=exim 4.96-RC0-14-24b8ed847-XX

Published CVSS scores

3.1Zero Day InitiativeCVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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