CVE-2016-1551

low

Published 2017-01-27 · Modified 2026-05-13

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CVSS v3

3.7

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v4 NEW

—

not yet in upstream

VIR risk

3.7

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.

Predictions

Exploit likelihood

47%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Debian Fixed 1 release

Version	Status	Fixed in
bullseye	Fixed	`0`

Application impact

Vendor	Product	Versions	Fixed
ntp	ntp	`4.2.8`
ntpsec	ntpsec	`a5fb34b9cc89b92a8fef2f459004865c93bb7f92`

References

CWEs

CWE-254

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.