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CVE-2016-1551

ntpd in NTP 4.2.8p3 and NTPsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 relies on the underlying operating system to protect it from…

Low3.7EPSS 2.2%
Published
Updated
Reserved
Assigned by
certcc

Description

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.

Scores

CVSS scores of CVE-2016-1551, by who scored it
Scored byCVSSScoreVector
NVDNVD · Modified3.0Low3.7CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS (exploitation in 30 days)
2.2% · top 17% of all CVEs (4 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.7.

Weakness

Affected products

  • NTP Project · NTP

    • affected 4.2.8p3
    • affected 4.2.8p4

  • NTPsec Project · NTPSec

    • affected 3e160db8dc248a0bcb053b56a80167dc742d2b74
    • affected a5fb34b9cc89b92a8fef2f459004865c93bb7f92

References (7)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .