CVE-2016-8858
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 29.5%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
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."
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 29.46% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-399, CWE-400
- Affected
- openbsd/openssh
- Source
- cve@mitre.org
EPSS 29.5% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126&r2=1.127&f=hIssue Tracking, Vendor Advisory
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127&content-type=text/x-cvsweb-markupIssue Tracking, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2016/10/19/3Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2016/10/20/1Mailing List, Third Party Advisory
- http://www.securityfocus.com/bid/93776Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037057Third Party Advisory, VDB Entry
- https://bugzilla.redhat.com/show_bug.cgi?id=1384860Issue Tracking
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sigPatch, Vendor Advisory
- https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89adIssue Tracking, Patch, Third Party Advisory
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.ascThird Party Advisory
- https://security.gentoo.org/glsa/201612-18Third Party Advisory
- https://security.netapp.com/advisory/ntap-20180201-0001/Third Party Advisory
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126&r2=1.127&f=hIssue Tracking, Vendor Advisory
- http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127&content-type=text/x-cvsweb-markupIssue Tracking, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2016/10/19/3Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2016/10/20/1Mailing List, Third Party Advisory
- http://www.securityfocus.com/bid/93776Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037057Third Party Advisory, VDB Entry
- https://bugzilla.redhat.com/show_bug.cgi?id=1384860Issue Tracking
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sigPatch, Vendor Advisory
- https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89adIssue Tracking, Patch, Third Party Advisory
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.ascThird Party Advisory
- https://security.gentoo.org/glsa/201612-18Third Party Advisory
- https://security.netapp.com/advisory/ntap-20180201-0001/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.