High
Security advisory
The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that "OpenSSH upstream does not consider this as a security issue."
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2016-8858
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:12 UTC · Revision 1
Source evidence
The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that "OpenSSH upstream does not consider this as a security issue."
osv:CVE-2016-8858
Complete source record
{
"id": "e7dfd33663ef75207cc472d856e75a91a8b00138db72cdb70c957ec8be5b4c8a",
"url": "https://osv.dev/vulnerability/CVE-2016-8858",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2016-8858",
"summary": "The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that \"OpenSSH upstream does not consider this as a security issue.\"",
"evidence": "osv:CVE-2016-8858",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2016-8858",
"aliases": [
"CVE-2016-8858"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/openssh/openssh-portable",
"type": "GIT",
"events": [
{
"introduced": "9f82e5a9042f2d872e98f48a876fcab3e25dd9bb"
},
{
"last_affected": "99522ba7ec6963a05c04a156bf20e3ba3605987c"
},
{
"fixed": "ec165c392ca54317dbe3064a8c200de6531e89ad"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:openbsd:openssh:6.8:*:*:*:*:*:*:*",
"range": [
{
"introduced": "6.8"
},
{
"last_affected": "6.8"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openbsd:openssh:6.9:*:*:*:*:*:*:*",
"range": [
{
"introduced": "6.9"
},
{
"last_affected": "6.9"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openbsd:openssh:7.0:*:*:*:*:*:*:*",
"range": [
{
"introduced": "7.0"
},
{
"last_affected": "7.0"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:openbsd:openssh:7.3:*:*:*:*:*:*:*",
"range": [
{
"introduced": "7.3"
},
{
"last_affected": "7.3"
}
],
"source": "CPE_STRING"
},
{
"range": [
{
"fixed": "ec165c392ca54317dbe3064a8c200de6531e89ad"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"6.8",
"6.9",
"7.0",
"7.3",
"V_7_3_P1",
"V_7_2_P1",
"V_7_1_P1",
"V_7_0_P1",
"V_6_9_P1",
"V_6_8_P1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2016-8858.json",
"vanir_signatures": [
{
"id": "CVE-2016-8858-2d5da5dc",
"digest": {
"threshold": 0.9,
"line_hashes": [
"156902939790282373310700724171657588209",
"316380331125517353126913904911828465574",
"295105781540324081782822153413707735107",
"244003011357174172644176527148363962509"
]
},
"source": "https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad",
"target": {
"file": "kex.c"
},
"deprecated": false,
"signature_type": "Line",
"signature_version": "v1"
},
{
"id": "CVE-2016-8858-dfa55b22",
"digest": {
"length": 1030,
"function_hash": "235425802652287821391024408040613178504"
},
"source": "https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad",
"target": {
"file": "kex.c",
"function": "kex_input_kexinit"
},
"deprecated": false,
"signature_type": "Function",
"signature_version": "v1"
}
],
"vanir_signatures_modified": "2026-10-20T13:19:37Z"
}
}
],
"modified": "2026-10-20T13:19:37.917885252Z",
"provider": "osv",
"references": [
"https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf",
"https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.asc",
"https://security.gentoo.org/glsa/201612-18",
"https://security.netapp.com/advisory/ntap-20180201-0001/",
"https://bugzilla.redhat.com/show_bug.cgi?id=1384860",
"https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sig",
"https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:a:openbsd:openssh:7.1:*:*:*:*:*:*:*",
"cpe:2.3:a:openbsd:openssh:7.2:*:*:*:*:*:*:*"
],
"vendor_product": "openbsd:openssh",
"extracted_events": [
{
"range": [
{
"introduced": "7.1"
},
{
"last_affected": "7.1"
},
{
"introduced": "7.2"
},
{
"last_affected": "7.2"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2016-8858",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 387518,
"published_at": "2016-12-09T11:59:00.207+00:00"
}