MediumFix available
dovecot — security advisory
An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. 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-2026-52687
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 05:07 UTC · Revision 1
Source evidence
An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. Update to non-vulnerable version. No publicly available exploits are known.
osv:DEBIAN-CVE-2026-52687
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": "df6c0d12d2e694a17adec1609b3cb7142e22446972f6fcd8cac971abb96314c8",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-52687",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-52687",
"summary": "An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. Update to non-vulnerable version. No publicly available exploits are known.",
"evidence": "osv:DEBIAN-CVE-2026-52687",
"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-2026-52687",
"aliases": [
"DEBIAN-CVE-2026-52687"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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-2026-52687.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-2026-52687.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-2026-52687.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-31T16:04:23.130295439Z",
"provider": "osv",
"upstream": [
"CVE-2026-52687"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-52687"
]
},
"related_cves": [
{
"value": "CVE-2026-52687",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 431228,
"published_at": "2026-08-28T12:16:30.133+00:00"
}