CVE-2020-13817

What it is

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data tampering, service disruption.

Exploit odds

3.4% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2020-06-04 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 02:53 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.4% in the next 30 days (EPSS).
• Severity: 7.4 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-06-04 13:15 UTC

Last modified

2026-06-17 02:53 UTC

Exploit probability

3.4% · EPSS, next 30 days

Weakness

CWE-330

Record status

Modified

Affected

• Ntp < 4.2.8
• Ntp < 4.3.100
• Ntp 4.2.8
• Netapp Cloud Backup
• Netapp Clustered Data Ontap
• Netapp Data Ontap
• Netapp Element Software
• Netapp Hci Management Node

Attack profile CVSS 3.1 · 7.4

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

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-2020-13817.md and follow it. Check whether this project is affected by CVE-2020-13817. 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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