MediumFix available
fetchmail — security advisory
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.
- Products
- fetchmail
- Affected versions
- 6.4.37-1, 6.4.38-1, 6.4.39-1, 6.5.6-1, 6.5.6-2, 6.5.7-1, 6.6.0-1, 6.6.1-1, 6.6.2-1, 6.6.2-2, 6.6.2-3, 6.6.3-1, 6.6.3-2, 6.6.3-3, 6.6.6-1, 6.6.8-1, 6.6.9-1
- Fixed versions
- 6.6.8-1
- CVEs
- CVE-2026-94184
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 01:50 UTC · Revision 1
Source evidence
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.
osv:DEBIAN-CVE-2026-94184
fetchmail
Fixed versions: Not specified
fetchmail
Fixed versions: Not specified
fetchmail
Fixed versions: 6.6.8-1
Complete source record
{
"id": "fca5c42f27e25d5e6c73ce65baf00c2dac4814efe6fcb432c60a0910572e69ec",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-94184",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-94184",
"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 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.",
"evidence": "osv:DEBIAN-CVE-2026-94184",
"products": [
{
"name": {
"value": "fetchmail",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.4.37-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.4.38-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.4.39-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.5.6-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.5.6-2",
"evidence": "/affected/0/versions"
},
{
"value": "6.5.7-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.2-2",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.2-3",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.3-2",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.3-3",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.6-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.8-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.6.9-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "fetchmail",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "6.4.39-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.5.6-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.5.6-2",
"evidence": "/affected/1/versions"
},
{
"value": "6.5.7-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.2-2",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.2-3",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.3-2",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.3-3",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.6-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.8-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.6.9-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "fetchmail",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "6.6.8-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "6.4.39-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.5.6-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.5.6-2",
"evidence": "/affected/2/versions"
},
{
"value": "6.5.7-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.2-2",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.2-3",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.3-1",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.3-2",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.3-3",
"evidence": "/affected/2/versions"
},
{
"value": "6.6.6-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-94184",
"aliases": [
"DEBIAN-CVE-2026-94184"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "fetchmail",
"purl": "pkg:deb/debian/fetchmail?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"6.4.37-1",
"6.4.38-1",
"6.4.39-1",
"6.5.6-1",
"6.5.6-2",
"6.5.7-1",
"6.6.0-1",
"6.6.1-1",
"6.6.2-1",
"6.6.2-2",
"6.6.2-3",
"6.6.3-1",
"6.6.3-2",
"6.6.3-3",
"6.6.6-1",
"6.6.8-1",
"6.6.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-94184.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "fetchmail",
"purl": "pkg:deb/debian/fetchmail?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"6.4.39-1",
"6.5.6-1",
"6.5.6-2",
"6.5.7-1",
"6.6.0-1",
"6.6.1-1",
"6.6.2-1",
"6.6.2-2",
"6.6.2-3",
"6.6.3-1",
"6.6.3-2",
"6.6.3-3",
"6.6.6-1",
"6.6.8-1",
"6.6.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-94184.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "6.6.8-1"
}
]
}
],
"package": {
"name": "fetchmail",
"purl": "pkg:deb/debian/fetchmail?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"6.4.39-1",
"6.5.6-1",
"6.5.6-2",
"6.5.7-1",
"6.6.0-1",
"6.6.1-1",
"6.6.2-1",
"6.6.2-2",
"6.6.2-3",
"6.6.3-1",
"6.6.3-2",
"6.6.3-3",
"6.6.6-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-94184.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-23T18:05:05.094647933Z",
"provider": "osv",
"upstream": [
"CVE-2026-94184"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-94184"
]
},
"related_cves": [
{
"value": "CVE-2026-94184",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 424258,
"published_at": "2026-09-21T15:17:38.547+00:00"
}