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Fencer Vulns
high 7.2

CVE-2016-1548 json

An attacker can spoof a packet from a legitimate ntpd server with an origin timestamp that matches the peer->dst timestamp recorded for tha…

published 2017-01-06 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-2643

cvss
7.2
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.8%
EPSS 3.8% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

An attacker can spoof a packet from a legitimate ntpd server with an origin timestamp that matches the peer->dst timestamp recorded for that server. After making this switch, the client in NTP 4.2.8p4 and earlier and NTPSec aa48d001683e5b791a743ec9c575aaf7d867a2b0c will reject all future legitimate server responses. It is possible to force the victim client to move time after the mode has been changed. ntpq gives no indication that the mode has been switched.

Patch / fix

  • ntp Debian 11 1:4.2.8p7+dfsg-1

debian advisories DEBIAN-CVE-2016-1548

  • ntp Ubuntu 14.04 LTS 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10
  • ntp Ubuntu 16.04 LTS 1:4.2.8p4+dfsg-3ubuntu5.3

ubuntu advisories UBUNTU-CVE-2016-1548

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.el6.1
  • ntp RHEL 7 4.2.6p5-22.el7_2.2
  • sntp RHEL 7 4.2.6p5-22.el7_2.2
  • ntpdate RHEL 6 4.2.6p5-10.el6.1
  • ntpdate RHEL 7 4.2.6p5-22.el7_2.2
  • ntp-perl RHEL 6 4.2.6p5-10.el6.1
  • ntp-perl RHEL 7 4.2.6p5-22.el7_2.2
  • ntp RHEL 6.7 EUS 4.2.6p5-5.el6_7.5

red hat advisories RHSA-2016:1552RHSA-2016:1141

  • ntp SLES for SAP 12, SLES 12, SLED 12 4.2.8p8-46.8.1
  • ntp SLES 11 SP3-TERADATA, SLES 11 SP3-LTSS, SLES 11 SP2-LTSS +3 more 4.2.8p7-44.1
  • ntp SLES 12 SP1, SLES 11 SP4, SLED 12 SP1 +2 more 4.2.8p7-11.1

suse advisories SUSE-SU-2016:1568-1SUSE-SU-2016:1471-1SUSE-SU-2016:1291-1SUSE-SU-2016:1278-1

  • 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-2016-1548 updated cvss 6.4

ntp: ntpd switching to interleaved mode with spoofed packets

  • Red Hat Enterprise Linux Client (v. 7) ntp 4.2.6p5-22.el7_2.2, ntpdate 4.2.6p5-22.el7_2.2 Red Hat Enterprise Linux Client Optional (v. 7) sntp 4.2.6p5-22.el7_2.2, ntp-perl 4.2.6p5-22.el7_2.2 Red Hat Enterprise Linux ComputeNode (v. 7) ntp 4.2.6p5-22.el7_2.2, ntpdate 4.2.6p5-22.el7_2.2 Red Hat Enterprise Linux ComputeNode Optional (v. 7) sntp 4.2.6p5-22.el7_2.2, ntp-perl 4.2.6p5-22.el7_2.2 Red Hat Enterprise Linux Desktop (v. 6) ntp 4.2.6p5-10.el6.1, ntpdate 4.2.6p5-10.el6.1 Red Hat Enterprise Linux Desktop Optional (v. 6) ntp-perl 4.2.6p5-10.el6.1
    +1 more products
    Red Hat Enterprise Linux HPC Node (v. 6) ntp 4.2.6p5-10.el6.1, ntpdate 4.2.6p5-10.el6.1
    fixed: vendor fix RHSA-2016:1141
  • Red Hat Enterprise Linux HPC Node EUS (v. 6.7) ntp 4.2.6p5-5.el6_7.5, ntpdate 4.2.6p5-5.el6_7.5
    fixed: vendor fix RHSA-2016:1552
  • Red Hat Enterprise Linux HPC Node Optional (v. 6) ntp-perl 4.2.6p5-10.el6.1
    fixed: vendor fix RHSA-2016:1141
  • Red Hat Enterprise Linux HPC Node Optional EUS (v. 6.7) ntp-perl 4.2.6p5-5.el6_7.5
    fixed: vendor fix RHSA-2016:1552
  • Red Hat Enterprise Linux Server (v. 6) ntp 4.2.6p5-10.el6.1, ntpdate 4.2.6p5-10.el6.1 Red Hat Enterprise Linux Server (v. 7) ntp 4.2.6p5-22.el7_2.2, ntpdate 4.2.6p5-22.el7_2.2
    fixed: vendor fix RHSA-2016:1141
  • Red Hat Enterprise Linux Server EUS (v. 6.7) ntp 4.2.6p5-5.el6_7.5, ntpdate 4.2.6p5-5.el6_7.5
    fixed: vendor fix RHSA-2016:1552
  • Red Hat Enterprise Linux Server Optional (v. 6) ntp-perl 4.2.6p5-10.el6.1 Red Hat Enterprise Linux Server Optional (v. 7) sntp 4.2.6p5-22.el7_2.2, ntp-perl 4.2.6p5-22.el7_2.2
    fixed: vendor fix RHSA-2016:1141
  • Red Hat Enterprise Linux Server Optional EUS (v. 6.7) ntp-perl 4.2.6p5-5.el6_7.5
    fixed: vendor fix RHSA-2016:1552
show 2 more
  • Red Hat Enterprise Linux Workstation (v. 6) ntp 4.2.6p5-10.el6.1, ntpdate 4.2.6p5-10.el6.1 Red Hat Enterprise Linux Workstation (v. 7) ntp 4.2.6p5-22.el7_2.2, ntpdate 4.2.6p5-22.el7_2.2 Red Hat Enterprise Linux Workstation Optional (v. 6) ntp-perl 4.2.6p5-10.el6.1 Red Hat Enterprise Linux Workstation Optional (v. 7) sntp 4.2.6p5-22.el7_2.2, ntp-perl 4.2.6p5-22.el7_2.2
    fixed: vendor fix RHSA-2016:1141
  • 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-21-103-11 updated cvss 7.2

Siemens TIM 4R-IE Devices

  • Siemens SIPLUS NET TIM 4R-IE (6AG1800-4BA00-7AA0) Siemens SIPLUS NET TIM 4R-IE DNP3 (6AG1803-4BA00-7AA0) Siemens TIM 4R-IE (6NH7800-4BA00) Siemens TIM 4R-IE DNP3 (6NH7803-4BA00-0AA0)
    affected: workaround, 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

cisa ICSA-21-159-11 updated cvss 7.2

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

3.81% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com http://www.talosintelligence.com/reports/TALOS-2016-0082/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.2 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P

Affected products

  • NTP Project NTP
  • NTPsec Project NTPSec

Classification

Weakness
  • CWE-19 Data Processing Errors

References

Sources

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.