CVE-2016-1548

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.8% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

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: 3.8% in the next 30 days (EPSS).
• Severity: 7.2 HIGH (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2017-01-06 21:59 UTC

Last modified

2026-06-17 00:42 UTC

Exploit probability

3.8% · EPSS, next 30 days

Weakness

CWE-19

Record status

Modified

Affected

• Ntp 4.2.8

Attack profile CVSS 3.0 · 7.2

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

Low

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-2016-1548.md and follow it. Check whether this project is affected by CVE-2016-1548. 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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