CVE-2015-7977

ntpd in NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (NULL pointer dereference) via a ntpdc reslist command.

Published: 2017-01-30 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-7977 is rated Moderate Risk (51.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 6.35%, 93th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize 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-2015-7977

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 2026-06-15 16.35% 6.35% -10.00%
2 2026-03-13 14.84% 16.35% +1.51%
3 2026-02-18 — 14.84% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-7977

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2015-7977

OS Trackers for CVE-2015-7977

vendor priority summary link
debian not yet assigned CVE-2015-7977 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-2015-7977
gentoo normal CVE-2015-7977: 1 GLSA(s) (201607-15), 1 atom(s) (net-misc/ntp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2015-7977
redhat medium — https://access.redhat.com/security/cve/CVE-2015-7977
suse medium CVE-2015-7977 severity moderate: SUSE including 32 source package names (ntp-4.2.6p5-25.el7, ntp-4.2.8p10-63.3, …), 95 product×package rows across 57 product lines (Image SLES12-SP5-Azure-BYOS, Image SLES12-SP5-Azure-Basic-On-Demand, … (57 product lines)): Fixed 95. https://www.suse.com/security/cve/CVE-2015-7977/
ubuntu medium CVE-2015-7977 medium priority: Ubuntu including 1 source packages (ntp), 8 status rows across 8 suites (precise, trusty, upstream, vivid, wily, xenial, yakkety, zesty): released 4, ignored 2, not-affected 2. https://ubuntu.com/security/CVE-2015-7977

Affected software / configurations for CVE-2015-7977

Vendor Product Version Raw CPE
ntp ntp <= 4.2.8 cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
ntp ntp >= 4.3.0, < 4.3.90 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:*:*:*:*:*:*
oracle linux 6 cpe:2.3:o:oracle:linux:6:-:*:*:*:*:*:*
siemens tim_4r-ie_firmware — cpe:2.3:o:siemens:tim_4r-ie_firmware:*:*:*:*:*:*:*:*
siemens tim_4r-ie_dnp3_firmware — cpe:2.3:o:siemens:tim_4r-ie_dnp3_firmware:-:*:*:*:*:*:*:*
netapp clustered_data_ontap — cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
netapp oncommand_balance — cpe:2.3:a:netapp:oncommand_balance:-:*:*:*:*:*:*:*
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:p5:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p6:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p7:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p8:*:*:*:*:*:*
freebsd freebsd 9.3 cpe:2.3:o:freebsd:freebsd:9.3:p9:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:-:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p1:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p10:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p12:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p15:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p16:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p17:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p18:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p19:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p2:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p22:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p24:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p25:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p26:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p27:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p3:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p4:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p5:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p6:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p7:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p8:*:*:*:*:*:*
freebsd freebsd 10.1 cpe:2.3:o:freebsd:freebsd:10.1:p9:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:-:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:p1:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:p10:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:p2:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:p5:*:*:*:*:*:*
freebsd freebsd 10.2 cpe:2.3:o:freebsd:freebsd:10.2:p7:*:*:*:*:*:*

References for CVE-2015-7977

URL Tags
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177507.html Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2016-January/176434.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00059.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00060.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00020.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00038.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html Broken Link
http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html Broken Link
http://lists.opensuse.org/opensuse-updates/2016-05/msg00114.html Broken Link
http://rhn.redhat.com/errata/RHSA-2016-0780.html Broken Link
http://rhn.redhat.com/errata/RHSA-2016-2583.html Broken Link
http://support.ntp.org/bin/view/Main/NtpBug2939 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-20160127-ntpd Third Party Advisory
http://www.debian.org/security/2016/dsa-3629 Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html Third Party Advisory
http://www.securityfocus.com/bid/81815 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1034782 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-3096-1 Third Party Advisory
https://bto.bluecoat.com/security-advisory/sa113 Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:09.ntp.asc Third Party Advisory
https://security.gentoo.org/glsa/201607-15 Third Party Advisory
https://security.netapp.com/advisory/ntap-20171031-0001/ Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11 Third Party Advisory US Government Resource
https://www.kb.cert.org/vuls/id/718152 Third Party Advisory US Government Resource
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