High
opensmtpd — security advisory
smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.
- Products
- opensmtpd
- Affected versions
- 5.3.3p1-4, 5.4.1p1-1, 5.4.1p1-1ubuntu0.1~esm1, 6.0.3p1-6, 6.0.3p1-6build1, 6.6.1p1-1, 6.6.1p1-3, 6.6.1p1-4, 6.6.1p1-5, 6.6.2p1-1, 6.6.4p1-1, 6.8.0p2-3, 6.8.0p2-4, 6.8.0p2-4build1, 7.3.0p1-1, 7.3.0p2-1, 7.4.0p1-1, 7.4.0p1-1build2, 7.4.0p1-1build4, 7.5.0p0-1, 7.7.0p0-1, 7.8.0p0-1, 7.8.0p0-2, 7.8.0p0-2build1
- Fixed versions
- Not specified
- CVEs
- CVE-2020-35680
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 01:29 UTC · Revision 1
Source evidence
smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.
osv:UBUNTU-CVE-2020-35680
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
opensmtpd
Fixed versions: Not specified
Complete source record
{
"id": "d66f76e872161cd5095c7416809e2bebd2eae04eb911eeed6a524b6510c979e6",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2020-35680",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2020-35680",
"summary": "smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.",
"evidence": "osv:UBUNTU-CVE-2020-35680",
"products": [
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{
"value": "5.3.3p1-4",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.1p1-1",
"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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"evidence": "/affected/2/versions"
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{
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{
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{
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{
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{
"value": "7.4.0p1-1",
"evidence": "/affected/3/versions"
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{
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"evidence": "/affected/3/versions"
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{
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{
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{
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"prerequisites": [],
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"affected_versions": [
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"evidence": "/affected/5/versions"
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{
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}
]
},
{
"name": {
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"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "7.7.0p0-1",
"evidence": "/affected/6/versions"
},
{
"value": "7.8.0p0-1",
"evidence": "/affected/6/versions"
},
{
"value": "7.8.0p0-2",
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}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2020-35680",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
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"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
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"purl": "pkg:deb/ubuntu/opensmtpd?arch=source&distro=esm-infra-legacy%2Ftrusty",
"ecosystem": "Ubuntu:Pro:14.04:LTS"
},
"versions": [
"5.3.3p1-4",
"5.4.1p1-1",
"5.4.1p1-1ubuntu0.1~esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-35680.json"
},
"ecosystem_specific": {
"binaries": [
{
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"binary_version": "5.4.1p1-1ubuntu0.1~esm1"
}
]
}
},
{
"ranges": [
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}
],
"package": {
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"purl": "pkg:deb/ubuntu/opensmtpd?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"6.0.3p1-6",
"6.0.3p1-6build1",
"6.6.1p1-1",
"6.6.1p1-3",
"6.6.1p1-4",
"6.6.1p1-5",
"6.6.2p1-1",
"6.6.4p1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-35680.json"
},
"ecosystem_specific": {
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},
{
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"package": {
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"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"6.8.0p2-3",
"6.8.0p2-4",
"6.8.0p2-4build1"
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"database_specific": {
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},
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{
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},
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
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],
"modified": "2026-10-17T12:56:56.025898830Z",
"provider": "osv",
"upstream": [
"CVE-2020-35680"
],
"references": [
"https://ubuntu.com/security/CVE-2020-35680",
"https://github.com/openbsd/src/commit/6c3220444ed06b5796dedfd53a0f4becd903c0d1",
"https://www.mail-archive.com/misc@opensmtpd.org/msg05188.html",
"https://poolp.org/posts/2020-12-24/december-2020-opensmtpd-6.8.0p1-released-fixed-several-bugs-proposed-several-diffs-book-is-on-github/",
"https://www.cve.org/CVERecord?id=CVE-2020-35680"
]
},
"related_cves": [
{
"value": "CVE-2020-35680",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 356552,
"published_at": "2020-12-24T16:15:00+00:00"
}