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Fencer Intel
medium 5.3

CVE-2016-7433 json

NTP before 4.2.8p9 does not properly perform the initial sync calculations, which allows remote attackers to unspecified impact via unknown…

published 2017-01-13 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-8286

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
9.8%
EPSS 9.8% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

NTP before 4.2.8p9 does not properly perform the initial sync calculations, which allows remote attackers to unspecified impact via unknown vectors, related to a "root distance that did not include the peer dispersion."

Patch / fix

  • ntp Debian 11 1:4.2.8p9+dfsg-1

debian advisories DEBIAN-CVE-2016-7433

  • ntp Ubuntu 16.04 LTS 1:4.2.8p4+dfsg-3ubuntu5.5

ubuntu advisories UBUNTU-CVE-2016-7433

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ntp RHEL 6 4.2.6p5-10.el6_8.2
  • ntp RHEL 7 4.2.6p5-25.el7_3.1
  • sntp RHEL 7 4.2.6p5-25.el7_3.1
  • ntpdate RHEL 6 4.2.6p5-10.el6_8.2
  • ntpdate RHEL 7 4.2.6p5-25.el7_3.1
  • ntp-perl RHEL 6 4.2.6p5-10.el6_8.2
  • ntp-perl RHEL 7 4.2.6p5-25.el7_3.1

red hat advisories RHSA-2017:0252

  • ntp SLES 11 SP3-TERADATA, SLES 11 SP3-LTSS, SLES 11 SP2-LTSS +4 more 4.2.8p9-48.9.1
  • ntp SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for Raspberry Pi 12 SP2 +4 more 4.2.8p9-55.1
  • ntp SLES for SAP 11 SP4, SLES 11 SP4 4.2.8p9-57.2
  • ntp SLES for SAP 12, SLES 12-LTSS 4.2.8p9-46.18.1

suse advisories SUSE-SU-2017:0255-1SUSE-SU-2016:3195-1SUSE-SU-2016:3196-1SUSE-SU-2016:3193-1

  • ntp openSUSE Tumbleweed 4.2.8p9-1.1

opensuse advisories openSUSE-SU-2024:10181-1

  • ntp Arch Linux 4.2.8.p9-1

arch linux advisories AVG-79AVG-80

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-2016-7433 updated cvss 2.9

ntp: Broken initial sync calculations regression

  • Red Hat Enterprise Linux Client (v. 7) ntp 4.2.6p5-25.el7_3.1, ntpdate 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux Client Optional (v. 7) sntp 4.2.6p5-25.el7_3.1, ntp-perl 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux ComputeNode (v. 7) ntp 4.2.6p5-25.el7_3.1, ntpdate 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux ComputeNode Optional (v. 7) sntp 4.2.6p5-25.el7_3.1, ntp-perl 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux Desktop (v. 6) ntp 4.2.6p5-10.el6_8.2, ntpdate 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Desktop Optional (v. 6) ntp-perl 4.2.6p5-10.el6_8.2
    +10 more products
    Red Hat Enterprise Linux HPC Node (v. 6) ntp 4.2.6p5-10.el6_8.2, ntpdate 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux HPC Node Optional (v. 6) ntp-perl 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Server (v. 6) ntp 4.2.6p5-10.el6_8.2, ntpdate 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Server (v. 7) ntp 4.2.6p5-25.el7_3.1, ntpdate 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux Server Optional (v. 6) ntp-perl 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Server Optional (v. 7) sntp 4.2.6p5-25.el7_3.1, ntp-perl 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux Workstation (v. 6) ntp 4.2.6p5-10.el6_8.2, ntpdate 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Workstation (v. 7) ntp 4.2.6p5-25.el7_3.1, ntpdate 4.2.6p5-25.el7_3.1 Red Hat Enterprise Linux Workstation Optional (v. 6) ntp-perl 4.2.6p5-10.el6_8.2 Red Hat Enterprise Linux Workstation Optional (v. 7) sntp 4.2.6p5-25.el7_3.1, ntp-perl 4.2.6p5-25.el7_3.1
    fixed: vendor fix RHSA-2017:0252
  • Red Hat Enterprise Linux 5 ntp
    not 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

cisa ICSA-21-159-11 updated cvss 5.3

Siemens SIMATIC NET CP 443-1 OPC UA

  • Siemens SIMATIC CP 443-1 OPC UA
    affected: mitigation, no fix planned

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

9.76% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Intel 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.