CVE-2016-4957 in the critical feed json
ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet.
published 2016-07-05 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-5931
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 44.9%
- EPSS 44.9% chance of exploitation in 30 days, percentile 98%
- public exploits
- 0
- none known
Summary
ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.
Patch / fix
- ntp Debian 11 1:4.2.8p8+dfsg-1
debian advisories DEBIAN-CVE-2016-4957
- ntp SLES 11 SP3-TERADATA, SLES 11 SP3-LTSS, SLES 11 SP2-LTSS +3 more 4.2.8p8-47.3
- ntp SLES 12 SP1, SLES 11 SP4, SLED 12 SP1 +2 more 4.2.8p8-14.1
- ntp SLES for SAP 12, SLES 12, SLED 12 4.2.8p8-46.8.1
suse advisories SUSE-SU-2016:1602-1SUSE-SU-2016:1584-1SUSE-SU-2016:1568-1SUSE-SU-2016:1563-1
- ntp openSUSE Tumbleweed 4.2.8p9-1.1
opensuse advisories openSUSE-SU-2024:10181-1
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2016-4957 updated cvss 5.0
ntp: crypto-NAK DoS (incorrect fix for CVE-2016-1547)
-
Red Hat Enterprise Linux 5 ntp Red Hat Enterprise Linux 6 ntp, ntpdate, ntp-perl Red Hat Enterprise Linux 7 ntp, sntp, ntpdate, ntp-perlnot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
Exploit prediction
44.94% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Classification
- Weakness
-
- CWE-476 NULL Pointer Dereference
References
-
support.ntp.org
/bin/view/Main/NtpBug3046
patch, vendor-advisory
-
lists.opensuse.org
/opensuse-security-announce/2016-06/msg00028.html
vendor-advisory, mailing-list, third-party-advisory
-
lists.opensuse.org
/opensuse-security-announce/2016-06/msg00023.html
vendor-advisory, mailing-list, third-party-advisory
-
security.freebsd.org
/advisories/FreeBSD-SA-16:24.ntp.asc
vendor-advisory, third-party-advisory
-
lists.opensuse.org
/opensuse-security-announce/2016-06/msg00024.html
vendor-advisory, mailing-list, third-party-advisory
-
lists.opensuse.org
/opensuse-security-announce/2016-06/msg00040.html
vendor-advisory, mailing-list, third-party-advisory
-
lists.opensuse.org
/opensuse-security-announce/2016-06/msg00018.html
vendor-advisory, mailing-list, third-party-advisory
-
security.gentoo.org
/glsa/201607-15
vendor-advisory, third-party-advisory
-
bugs.ntp.org
/3046
issue-tracking, vendor-advisory
-
support.ntp.org
/bin/view/Main/SecurityNotice
release-notes, vendor-advisory
-
securitytracker.com
/id/1036037
vdb-entry, third-party-advisory
-
oracle.com
/technetwork/topics/security/bulletinapr2016-2952098.html
third-party-advisory
-
kb.cert.org
/vuls/id/321640
third-party-advisory, us-government-resource
Sources
- CVE List CVE-2016-4957
- NVD CVE-2016-4957
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.