---
id: CVE-2026-94184
title: >-
  A stack-based buffer overflow flaw was found in fetchmail when built with NTLM
  support
summary: >-
  A stack-based buffer overflow flaw was found in fetchmail when built with NTLM
  support. A malicious or compromised mail server advertising NTLM
  authentication can send a crafted Type 2 challenge that causes fetchmail to
  write past a fixe…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-121
vendor: Red Hat
product: fetchmail
affected:
  - fetchmail (all versions)
  - fetchmail (all versions)
  - fetchmail (all versions)
  - fetchmail (all versions)
  - fetchmail (all versions)
published: '2026-09-21'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T19:19:48.907'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-94184'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-94184'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2537395'
    label: secalert@redhat.com
  - url: >-
      https://gitlab.com/fetchmail/fetchmail/-/commit/cb5be5c38471eec19e519ace0bc569176317ea92
    label: secalert@redhat.com
  - url: 'https://www.fetchmail.info/fetchmail-SA-2026-01.txt'
    label: secalert@redhat.com
  - url: 'https://www.openwall.com/lists/oss-security/2026/06/27/8'
    label: secalert@redhat.com
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/23/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-94184.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-94184'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-94184'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-22T03:55:50.026928Z'
epss: 0.01219
epssPercentile: 0.67345
ingestedAt: '2026-09-21T14:38:56.368Z'
---

## Overview

A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening.

Affects v5.0.8 through v6.6.6.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-94184.json)