Vulnerability
CVE-2016-1551
CVE-2016-1551 is a low-severity vulnerability (CVSS v3.0 3.7). As of 2026-11-11, no host in our data shows software it affects on an open service.
ntpd in NTP 4.2.8p3 and NTPsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 relies on the underlying operating system to protect it from requests that impersonate reference clocks. Because reference clocks are treated like other peers and stored in the same structure, any packet with a source ip address of a reference clock (127.127.1.1 for example) that reaches the receive() function will match that reference clock's peer record and will be treated as a trusted peer. Any system that lacks the typical martian packet filtering which would block these packets is in danger of having its time controlled by an attacker.
- Published
- 2017-01-27
- Last modified
- 2026-06-17
- CVSS score
- 3.7 CVSS v3.0
- CVSS vector (v3.0)
- CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Exploit likelihood (EPSS)
- 2.2% in the next 30 days (top 18% of CVEs)
Exposure in our data
0 hosts
Hosts whose banner shows an affected software version on a service open at their latest check.
Not counted: 1 459 hosts where the software version is too vague to tell (only a major release).
Counted 2026-11-11 04:20 UTC
By country
Not seen on any scanned host.
Affected software seen
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