CVE-2016-9310 Ntp CVE debrief

Who should care

Administrators and operators running ntpd/NTP before 4.2.8p9 should care, along with vendors and maintainers who ship NTP-based packages or appliances. Environments that expose ntpd control traffic or rely on trap handling for monitoring deserve particular attention.

Technical summary

The vulnerability is in ntpd's control mode (mode 6) functionality. A crafted control mode packet can cause remote trap set/unset behavior, indicating improper handling of control messages. NVD maps the issue to versions through 4.2.8, and the vendor release notes reference the fix in 4.2.8p9. The supplied NVD record classifies the weakness as CWE-400 and gives a network-only attack vector with low confidentiality and availability impact.

Defensive priority

Medium. Patch promptly if you run affected NTP/ntpd versions, especially on exposed or operationally important systems. While the supplied data does not indicate KEV status or active exploitation, the issue is remotely reachable and affects a core time-synchronization service.

Recommended defensive actions

• Upgrade NTP/ntpd to 4.2.8p9 or to a vendor package that includes the fix.
• Review vendor advisories for your platform to confirm the corrected package version.
• Limit exposure of ntpd control traffic to trusted management networks where operationally feasible.
• Verify whether any monitoring or automation depends on ntpd trap behavior and test after updating.
• Track downstream security advisories from your OS or appliance vendor for backported fixes.

Evidence notes

This debrief is based only on the supplied CVE/NVD corpus and linked vendor references. The CVE was published on 2017-01-13 and the NVD record was later modified on 2026-05-13; timing context here uses the CVE publication date, not the later modification date. The source corpus includes the NTP 4.2.8p9 release notes, NtpBug3118, and vendor advisories that align with the affected-version and remediation guidance.

Official resources