---
id: CVE-2026-94054
title: >-
  Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled
  proxy, has an out-of-bounds write.
summary: >-
  Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled
  proxy, has an out-of-bounds write.
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L'
cwe:
  - CWE-787
vendor: exim
product: exim
affected:
  - exim < 4.100.1
patched:
  - exim 4.100.1
published: '2026-09-19'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:47:34.840'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-94054'
references:
  - url: 'https://lists.exim.org/lurker/message/20260918.121220.0f87338e.en.html'
    label: cve@mitre.org
tags:
  - nvd
  - cve.org
epss: 0.00268
epssPercentile: 0.16895
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-22T16:06:57.411463Z'
ingestedAt: '2026-09-19T23:10:34.248Z'
---

## Overview

Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled proxy, has an out-of-bounds write.

## Affected

- `exim < 4.100.1`

## Remediation

Upgrade past the affected range:

- `exim 4.100.1`