No exploitation reported

CVE-2016-1548

No exploitation reported by the sources we read.

Published2017-01-06
WeaknessCWE-19

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2017-01-0621:59CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2016-1548?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-1548?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Ntp

Branch	Affected	Fixed in	Source
4.2	= 4.2.8	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-21-103-11 CISA4 known affected
Siemens TIM 4R-IE Devices
SIPLUS NET TIM 4R-IE (6AG1800-4BA00-7AA0) · SIPLUS NET TIM 4R-IE DNP3 (6AG1803-4BA00-7AA0) · TIM 4R-IE (6NH7800-4BA00) · +1 more

Full record on NVD

Fix

Workaround from the vendor CISA ICSA-21-103-11 · 4 productsDeactivate NTP-based time syncronization of the device, if enabled. The feature is disabled by default.
Workaround from the vendor CISA ICSA-21-103-11 · 4 productsConfigure an additional firewall to prevent communication to the port udp/123 of an affected device.
No fix planned, says the vendor CISA ICSA-21-103-11 · 4 productsCurrently no fix is planned

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.07.2read 2026-10-23
NVDCVSS 2.06.4read 2026-10-23
NVDweakness (CWE)CWE-19read 2026-10-23
FIRST EPSSEPSS score3.8 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L
Published: 2017-01-06
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-1548?

Is CVE-2016-1548 actively exploited?

Active exploitation of CVE-2016-1548 has not been confirmed. Its EPSS score was 3.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-1548?

CVE-2016-1548 has a CVSS v3 base score of 7.2 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L.

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