CVE-2016-8858

high-risk
Published 2016-12-09

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."

Do I need to act?

!
27.1% chance of exploitation in next 30 days
EPSS score — higher than 73% of all CVEs
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (6)

Affected Vendors

Openbsd

References (26)

Issue Tracking http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126&r2=...
Issue Tracking http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127&content...
Mailing List http://www.openwall.com/lists/oss-security/2016/10/19/3
Mailing List http://www.openwall.com/lists/oss-security/2016/10/20/1
Third Party Advisory http://www.securityfocus.com/bid/93776
Third Party Advisory http://www.securitytracker.com/id/1037057
Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=1384860
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
Patch https://ftp.openbsd.org/pub/OpenBSD/patches/6.0/common/013_ssh_kexinit.patch.sig
Issue Tracking https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200...
Third Party Advisory https://security.FreeBSD.org/advisories/FreeBSD-SA-16:33.openssh.asc
Third Party Advisory https://security.gentoo.org/glsa/201612-18
Third Party Advisory https://security.netapp.com/advisory/ntap-20180201-0001/
Issue Tracking http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c.diff?r1=1.126&r2=...
Issue Tracking http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/kex.c?rev=1.127&content...
Mailing List http://www.openwall.com/lists/oss-security/2016/10/19/3
Mailing List http://www.openwall.com/lists/oss-security/2016/10/20/1
Third Party Advisory http://www.securityfocus.com/bid/93776
Third Party Advisory http://www.securitytracker.com/id/1037057
Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=1384860
and 6 more references
54
/ 100
high-risk
Severity 26/34 · High
Exploitability 15/34 · Moderate
Exposure 13/34 · Low