MediumFix available
dovecot — security advisory
An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.
- Products
- dovecot
- Affected versions
- 1:2.3.19.1+dfsg1-2.1, 1:2.3.19.1+dfsg1-2.1+deb12u1, 1:2.3.19.1+dfsg1-2.1+deb12u2, 1:2.3.19.1+dfsg1-2.1+deb12u3, 1:2.3.19.1+dfsg1-2.1+deb12u4, 1:2.3.19.1+dfsg1-2.1+deb12u5, 1:2.3.19.1+dfsg1-2.1+deb12u6, 1:2.4.1+dfsg1-6, 1:2.4.1+dfsg1-6+deb13u1, 1:2.4.1+dfsg1-6+deb13u2, 1:2.4.1+dfsg1-6+deb13u3, 1:2.4.1+dfsg1-6+deb13u4, 1:2.4.1+dfsg1-6+deb13u5, 1:2.4.1+dfsg1-6+deb13u6, 1:2.4.1+dfsg1-7, 1:2.4.1+dfsg1-8, 1:2.4.1+dfsg1-9, 1:2.4.2+dfsg1-1, 1:2.4.2+dfsg1-2, 1:2.4.2+dfsg1-3, 1:2.4.2+dfsg1-4, 1:2.4.3+dfsg1-1, 1:2.4.3+dfsg1-2, 1:2.4.4+dfsg1-1, 1:2.4.4+dfsg1-2
- Fixed versions
- 1:2.3.19.1+dfsg1-2.1+deb12u7, 1:2.4.1+dfsg1-6+deb13u7, 1:2.4.5+dfsg1-1
- CVEs
- CVE-2026-40014
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 03:15 UTC · Revision 1
Source evidence
An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.
osv:DEBIAN-CVE-2026-40014
dovecot
Fixed versions: 1:2.3.19.1+dfsg1-2.1+deb12u7
dovecot
Fixed versions: 1:2.4.1+dfsg1-6+deb13u7
dovecot
Fixed versions: 1:2.4.5+dfsg1-1
Complete source record
{
"id": "9b30f42bb806a53aaf0c1b98fb99c3e8725f785bbbf7b01bf3ed2577054e88f5",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-40014",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-40014",
"summary": "An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.",
"evidence": "osv:DEBIAN-CVE-2026-40014",
"products": [
{
"name": {
"value": "dovecot",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u7",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "1:2.3.19.1+dfsg1-2.1",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u2",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u3",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u4",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u5",
"evidence": "/affected/0/versions"
},
{
"value": "1:2.3.19.1+dfsg1-2.1+deb12u6",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "dovecot",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:2.4.1+dfsg1-6+deb13u7",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "1:2.4.1+dfsg1-6",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u3",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u4",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u5",
"evidence": "/affected/1/versions"
},
{
"value": "1:2.4.1+dfsg1-6+deb13u6",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "dovecot",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:2.4.5+dfsg1-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "1:2.4.1+dfsg1-6",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.1+dfsg1-7",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.1+dfsg1-8",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.1+dfsg1-9",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.2+dfsg1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.2+dfsg1-2",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.2+dfsg1-3",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.2+dfsg1-4",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.3+dfsg1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.3+dfsg1-2",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.4+dfsg1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1:2.4.4+dfsg1-2",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-40014",
"aliases": [
"DEBIAN-CVE-2026-40014"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.3.19.1+dfsg1-2.1+deb12u7"
}
]
}
],
"package": {
"name": "dovecot",
"purl": "pkg:deb/debian/dovecot?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1:2.3.19.1+dfsg1-2.1",
"1:2.3.19.1+dfsg1-2.1+deb12u1",
"1:2.3.19.1+dfsg1-2.1+deb12u2",
"1:2.3.19.1+dfsg1-2.1+deb12u3",
"1:2.3.19.1+dfsg1-2.1+deb12u4",
"1:2.3.19.1+dfsg1-2.1+deb12u5",
"1:2.3.19.1+dfsg1-2.1+deb12u6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40014.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.4.1+dfsg1-6+deb13u7"
}
]
}
],
"package": {
"name": "dovecot",
"purl": "pkg:deb/debian/dovecot?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1:2.4.1+dfsg1-6",
"1:2.4.1+dfsg1-6+deb13u1",
"1:2.4.1+dfsg1-6+deb13u2",
"1:2.4.1+dfsg1-6+deb13u3",
"1:2.4.1+dfsg1-6+deb13u4",
"1:2.4.1+dfsg1-6+deb13u5",
"1:2.4.1+dfsg1-6+deb13u6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40014.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.4.5+dfsg1-1"
}
]
}
],
"package": {
"name": "dovecot",
"purl": "pkg:deb/debian/dovecot?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1:2.4.1+dfsg1-6",
"1:2.4.1+dfsg1-7",
"1:2.4.1+dfsg1-8",
"1:2.4.1+dfsg1-9",
"1:2.4.2+dfsg1-1",
"1:2.4.2+dfsg1-2",
"1:2.4.2+dfsg1-3",
"1:2.4.2+dfsg1-4",
"1:2.4.3+dfsg1-1",
"1:2.4.3+dfsg1-2",
"1:2.4.4+dfsg1-1",
"1:2.4.4+dfsg1-2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40014.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-31T16:04:23.061479954Z",
"provider": "osv",
"upstream": [
"CVE-2026-40014"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-40014"
]
},
"related_cves": [
{
"value": "CVE-2026-40014",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 427027,
"published_at": "2026-08-28T12:16:28.24+00:00"
}