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.
{
"unresolved_ranges": [
{
"extracted_events": [
{
"fixed": "6.8.0"
}
],
"source": "CPE_RANGE",
"vendor_product": "opensmtpd:opensmtpd",
"cpes": [
"cpe:2.3:a:opensmtpd:opensmtpd:*:*:*:*:*:*:*:*"
]
},
{
"extracted_events": [
{
"introduced": "32"
},
{
"last_affected": "32"
},
{
"introduced": "33"
},
{
"last_affected": "33"
}
],
"source": "CPE_STRING",
"vendor_product": "fedoraproject:fedora",
"cpes": [
"cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
]
},
{
"extracted_events": [
{
"introduced": "6.8.0-NA"
},
{
"last_affected": "6.8.0-NA"
}
],
"source": "CPE_STRING",
"vendor_product": "opensmtpd:opensmtpd",
"cpes": [
"cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:-:*:*:*:*:*:*"
]
}
]
}"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-35680.json"
[
{
"target": {
"file": "usr.sbin/smtpd/lka_filter.c"
},
"deprecated": false,
"source": "https://github.com/openbsd/src/commit/6c3220444ed06b5796dedfd53a0f4becd903c0d1",
"id": "CVE-2020-35680-5a2407e5",
"signature_version": "v1",
"digest": {
"threshold": 0.9,
"line_hashes": [
"146958479146620846539546414962359749417",
"331739472224798831840993251905507474107",
"91893901251692159920292890227734731430",
"279425024596136944150789901713018609996",
"302454195925576915379956718349724179184",
"102226086405913718666762852662536102668",
"156377891668464352413748805278213613186",
"294224973442606065565798747585475670296"
]
},
"signature_type": "Line"
},
{
"target": {
"function": "filter_session_io",
"file": "usr.sbin/smtpd/lka_filter.c"
},
"deprecated": false,
"source": "https://github.com/openbsd/src/commit/6c3220444ed06b5796dedfd53a0f4becd903c0d1",
"id": "CVE-2020-35680-e9b83694",
"signature_version": "v1",
"digest": {
"length": 477.0,
"function_hash": "139574854378595409949297631104406793897"
},
"signature_type": "Function"
}
]
"2026-07-09T00:22:05Z"
{
"extracted_events": [
{
"introduced": "6.8.0-patch1\\-rc1"
},
{
"last_affected": "6.8.0-patch1\\-rc1"
}
],
"source": "CPE_STRING",
"cpe": "cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:patch1-rc1:*:*:*:*:*:*"
}