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CVE-2016-7429 Ntp CVE debrief

CVE-2016-7429 is a low-severity NTP vulnerability that can disrupt communication with a time source. According to the CVE record, versions before 4.2.8p9 may change peer state based on the interface that receives a response, which can allow a remote attacker to interfere with synchronization by sending a response to the wrong interface.

Vendor
Ntp
Product
CVE-2016-7429
CVSS
LOW 3.7
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-13
Original CVE updated
2026-05-13
Advisory published
2017-01-13
Advisory updated
2026-05-13

Who should care

Organizations running affected NTP releases, especially systems that rely on NTP for time synchronization and expose reachable network paths where spoofed or misrouted responses could be delivered.

Technical summary

The NVD description says NTP before 4.2.8p9 may change the peer structure to the interface that receives a response from a source. If a response for a source is sent to an interface that the source does not use, the peer can be re-associated in a way that prevents communication with that source. NVD classifies the impact as availability-only (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L) and maps the issue to CWE-18.

Defensive priority

Moderate for fleets that depend on NTP correctness, even though the CVSS score is low. Time synchronization problems can have knock-on effects for authentication, logging, scheduling, and distributed systems, so affected versions should be updated promptly.

Recommended defensive actions

  • Upgrade NTP to 4.2.8p9 or a later vendor-supported release that includes the fix.
  • Review vendor advisories and downstream package errata for your platform before maintenance windows.
  • Confirm which systems run affected NTP packages or embedded NTP components and prioritize externally reachable hosts first.
  • Monitor for unusual NTP behavior or unexpected loss of communication with configured time sources after remediation.
  • Use the official NTP security notice and release notes as the primary remediation references for this CVE.

Evidence notes

This debrief is based on the supplied NVD/CVE record, which lists the vulnerability description, affected version boundary, CVSS vector, CWE mapping, and official/vendor references. The CVE record was published on 2017-01-13 and later modified on 2026-05-13. The referenced NTP release notes and NTP bug/security notice are the most relevant vendor sources in the provided corpus.

Official resources

Published by the CVE record on 2017-01-13. The record was modified on 2026-05-13; that modification date should not be treated as the original disclosure date.