CVE-2016-2518

The MATCH_ASSOC function in NTP before version 4.2.8p9 and 4.3.x before 4.3.92 allows remote attackers to cause an out-of-bounds reference via an addpeer request with a large hmode value.

Published: 2017-01-30 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-2518 is rated Moderate Risk (53.3/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.48%). EPSS rose +1.44% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-2518

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-03 2.04% 3.48% +1.44%
2 2026-03-29 1.60% 2.04% +0.44%
3 2026-01-14 — 1.60% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-2518

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2016-2518

OS Trackers for CVE-2016-2518

vendor priority summary link
debian not yet assigned CVE-2016-2518 not yet assigned priority: Debian including 1 source packages (ntp), 1 status rows across 1 suites (bullseye): resolved 1. https://security-tracker.debian.org/tracker/CVE-2016-2518
gentoo normal CVE-2016-2518: 1 GLSA(s) (201607-15), 1 atom(s) (net-misc/ntp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-2518
redhat low — https://access.redhat.com/security/cve/CVE-2016-2518
suse low CVE-2016-2518 severity low: SUSE including 27 source package names (ntp-4.2.6p5-22.el7_2.2, ntp-4.2.8p10-63.3, …), 85 product×package rows across 55 product lines (Image SLES12-SP5-Azure-BYOS, Image SLES12-SP5-Azure-Basic-On-Demand, … (55 product lines)): Fixed 85. https://www.suse.com/security/cve/CVE-2016-2518/
ubuntu low CVE-2016-2518 low priority: Ubuntu including 1 source packages (ntp), 7 status rows across 7 suites (precise, trusty, upstream, wily, xenial, yakkety, zesty): released 4, not-affected 2, ignored 1. https://ubuntu.com/security/CVE-2016-2518

Affected software / configurations for CVE-2016-2518

Vendor Product Version Raw CPE
ntp ntp < 4.2.8 cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
ntp ntp >= 4.3.0, < 4.3.92 cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta4:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta5:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p5:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p6:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p8:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
netapp clustered_data_ontap — cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
netapp data_ontap — cpe:2.3:a:netapp:data_ontap:-:*:*:*:*:7-mode:*:*
netapp oncommand_balance — cpe:2.3:a:netapp:oncommand_balance:-:*:*:*:*:*:*:*
netapp oncommand_performance_manager — cpe:2.3:a:netapp:oncommand_performance_manager:-:*:*:*:*:*:*:*
netapp oncommand_unified_manager_for_clustered_data_ontap — cpe:2.3:a:netapp:oncommand_unified_manager_for_clustered_data_ontap:-:*:*:*:*:*:*:*
oracle communications_user_data_repository 10.0.0 cpe:2.3:a:oracle:communications_user_data_repository:10.0.0:*:*:*:*:*:*:*
oracle communications_user_data_repository 10.0.1 cpe:2.3:a:oracle:communications_user_data_repository:10.0.1:*:*:*:*:*:*:*
oracle communications_user_data_repository 12.0.0 cpe:2.3:a:oracle:communications_user_data_repository:12.0.0:*:*:*:*:*:*:*
oracle linux 6 cpe:2.3:o:oracle:linux:6:-:*:*:*:*:*:*
oracle linux 7 cpe:2.3:o:oracle:linux:7:-:*:*:*:*:*:*
redhat enterprise_linux_desktop 7.0 cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 6.0 cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 7.0 cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.3 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.5 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.7 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.7:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.3 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.3:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.7 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.7:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 6.0 cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:-:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p1:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p10:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p12:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p13:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p16:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p19:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p2:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p20:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p21:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p22:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p23:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p24:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p25:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p28:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p3:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p30:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p31:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p32:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p33:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p34:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p35:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p36:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p38:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p39:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p5:*:*:*:*:*:*

References for CVE-2016-2518

URL Tags
http://lists.fedoraproject.org/pipermail/package-announce/2016-May/183647.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-May/184669.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00034.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00037.html
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00052.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.html
http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
http://lists.opensuse.org/opensuse-updates/2016-05/msg00114.html
http://packetstormsecurity.com/files/136864/Slackware-Security-Advisory-ntp-Updates.html
http://rhn.redhat.com/errata/RHSA-2016-1552.html Broken Link
http://support.ntp.org/bin/view/Main/NtpBug3009 Vendor Advisory
http://support.ntp.org/bin/view/Main/SecurityNotice#April_2016_ntp_4_2_8p7_Security Vendor Advisory
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160428-ntpd
http://www.debian.org/security/2016/dsa-3629 Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html Patch Third Party Advisory
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html Third Party Advisory
http://www.securityfocus.com/archive/1/538233/100/0/threaded
http://www.securityfocus.com/archive/1/archive/1/538233/100/0/threaded
http://www.securityfocus.com/bid/88226 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1035705 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-3096-1
https://access.redhat.com/errata/RHSA-2016:1141 Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:16.ntp.asc Third Party Advisory
https://security.gentoo.org/glsa/201607-15 Third Party Advisory
https://security.netapp.com/advisory/ntap-20171004-0002/ Third Party Advisory
https://support.f5.com/csp/article/K20804323
https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11
https://www.debian.org/security/2016/dsa-3629
https://www.kb.cert.org/vuls/id/718152 Third Party Advisory US Government Resource
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