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PatchSiren cyber security CVE debrief

CVE-2016-2519 Ntp CVE debrief

CVE-2016-2519 is a remote denial-of-service issue in ntpd. A large request data value can make ctl_getitem return NULL, and the daemon may abort instead of handling the input safely. NVD rates the issue 5.9 (medium), with network access required but no privileges or user interaction.

Vendor
Ntp
Product
CVE-2016-2519
CVSS
MEDIUM 5.9
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-30
Original CVE updated
2026-05-13
Advisory published
2017-01-30
Advisory updated
2026-05-13

Who should care

Administrators and platform teams running affected NTP/ntpd deployments, especially systems reachable from untrusted networks or exposing ntpd control functionality.

Technical summary

According to the CVE/NVD record, ntpd in NTP before 4.2.8p7 and 4.3.x before 4.3.92 can be driven into an abort condition when a large request data value causes ctl_getitem to return NULL. NVD maps the issue to CWE-119 and scores it CVSS 3.0 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Defensive priority

Medium. The impact is service availability only, but affected ntpd processes can abort remotely, so exposed or widely used time services should be patched promptly.

Recommended defensive actions

  • Upgrade NTP to 4.2.8p7 or later, or 4.3.92 or later, as applicable.
  • Verify deployed packages against the affected version ranges in the NVD record.
  • Restrict access to ntpd control interfaces and only allow trusted hosts where feasible.
  • Monitor for unexpected ntpd aborts, crashes, or restart behavior until remediation is complete.
  • Apply vendor-specific guidance from ntp.org and downstream advisories such as FreeBSD, Gentoo, Oracle, CERT/CC, and NetApp.

Evidence notes

This debrief uses the CVE/NVD record published on 2017-01-30 and its official references. The NVD record was modified on 2026-05-13, but that date reflects record maintenance, not the original disclosure. Vendor and downstream advisories in the source corpus include ntp.org, Oracle, FreeBSD, Gentoo, NetApp, and CERT/CC.

Official resources

The CVE record was published on 2017-01-30 and later modified on 2026-05-13; the latter is a record update, not the original disclosure date. No KEV entry was provided in the source corpus.