CVE-2016-8858
Summary
| CVE | CVE-2016-8858 |
|---|---|
| State | PUBLISHED |
| Assigner | mitre |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2016-12-09 11:59:00 UTC |
| Updated | 2026-05-06 22:30:45 UTC |
| Description | 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." |
Risk And Classification
Primary CVSS: v3.0 7.5 HIGH from [email protected]
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.268660000 probability, percentile 0.963960000 (date 2026-05-10)
Problem Types: CWE-399 | n/a
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.0 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 2.0 | [email protected] | Primary | 7.8 | AV:N/AC:L/Au:N/C:N/I:N/A:C |
CVSS v3.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2.0 Breakdown
Access Vector
NetworkAccess Complexity
LowAuthentication
NoneConfidentiality
NoneIntegrity
NoneAvailability
CompleteAV:N/AC:L/Au:N/C:N/I:N/A:C
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Openbsd | Openssh | 6.8 | All | All | All |
| Application | Openbsd | Openssh | 6.9 | All | All | All |
| Application | Openbsd | Openssh | 7.0 | All | All | All |
| Application | Openbsd | Openssh | 7.1 | All | All | All |
| Application | Openbsd | Openssh | 7.2 | All | All | All |
| Application | Openbsd | Openssh | 7.3 | All | All | All |
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.asc | af854a3a-2127-422b-91ae-364da2661108 | security.FreeBSD.org | Third Party Advisory |
| ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sig | af854a3a-2127-422b-91ae-364da2661108 | ftp.openbsd.org | Patch, Vendor Advisory |
| Bug 1384860 – CVE-2016-8858 openssh: Memory exhaustion due to unregistered KEXINIT handler after receiving message | af854a3a-2127-422b-91ae-364da2661108 | bugzilla.redhat.com | Issue Tracking |
| upstream commit · openssh/openssh-portable@ec165c3 · GitHub | af854a3a-2127-422b-91ae-364da2661108 | github.com | Issue Tracking, Patch, Third Party Advisory |
| OpenSSH 'ssh/kex.c' Denial of Service Vulnerability | af854a3a-2127-422b-91ae-364da2661108 | www.securityfocus.com | Third Party Advisory, VDB Entry |
| CVE-2016-8858 OpenSSH Vulnerability in NetApp Products | NetApp Product Security | af854a3a-2127-422b-91ae-364da2661108 | security.netapp.com | Third Party Advisory |
| OpenSSH Key Exchange Initialization Bug in kex_input_kexinit() Lets Remote Users Consume Excessive Memory Resources - SecurityTracker | af854a3a-2127-422b-91ae-364da2661108 | www.securitytracker.com | Third Party Advisory, VDB Entry |
| src/usr.bin/ssh/kex.c - view - 1.127 | af854a3a-2127-422b-91ae-364da2661108 | cvsweb.openbsd.org | Issue Tracking, Vendor Advisory |
| oss-security - CVE Request: OpenSSH: Memory exhaustion issue found in OpenSSH | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Third Party Advisory |
| src/usr.bin/ssh/kex.c - diff - 1.127 | af854a3a-2127-422b-91ae-364da2661108 | cvsweb.openbsd.org | Issue Tracking, Vendor Advisory |
| cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf | af854a3a-2127-422b-91ae-364da2661108 | cert-portal.siemens.com | |
| OpenSSH: Multiple vulnerabilities (GLSA 201612-18) — Gentoo security | af854a3a-2127-422b-91ae-364da2661108 | security.gentoo.org | Third Party Advisory |
| oss-security - Re: Re: CVE Request: OpenSSH: Memory exhaustion issue found in OpenSSH | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Third Party Advisory |
| Exploit not working in 6.6.p1 · Issue #1 · dag-erling/kexkill · GitHub | MITRE | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Legacy QID Mappings
- 591280 Siemens SCALANCE X-200RNA Switch Devices Denial of Service (DoS) Multiple Vulnerabilities (ICSA-22-349-21, SSA-412672)