CVE-2016-1549

What it is

A malicious authenticated peer can create arbitrarily-many ephemeral associations in order to win the clock selection algorithm in ntpd in NTP 4.2.8p4 and earlier and NTPsec 3e160db8dc248a0bcb053b56a80167dc742d2b74 and a5fb34b9cc89b92a8fef2f459004865c93bb7f92 and modify a victim's clock.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data tampering.

Exploit odds

3.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2017-01-06 21:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 00:42 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.1% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2017-01-06 21:59 UTC

Last modified

2026-06-17 00:42 UTC

Exploit probability

3.1% · EPSS, next 30 days

Weakness

CWE-19

Record status

Modified

Affected

• Ntp 4.2.8

Attack profile CVSS 3.0 · 6.5

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2016-1549.md and follow it. Check whether this project is affected by CVE-2016-1549. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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