CVE-2016-2518 Freebsd CVE debrief

Who should care

Administrators and maintainers of systems that run affected NTP packages should care, especially if the service is network-reachable or part of critical time-synchronization infrastructure. This includes downstream OS/package builds referenced in the advisory corpus, such as FreeBSD and multiple Linux distributions.

Technical summary

The bug is in the MATCH_ASSOC function in NTP. According to the NVD record, a malformed addpeer request with an oversized hmode value can cause an out-of-bounds reference. The official CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, and NVD lists CWE-125 as the primary weakness. The affected scope in the corpus covers upstream NTP versions before 4.2.8p9 and 4.3.x before 4.3.92, plus downstream package advisories.

Defensive priority

Medium. Treat as a network-reachable, unauthenticated availability issue in core time-sync infrastructure and prioritize exposed or operationally critical NTP deployments.

Recommended defensive actions

• Upgrade NTP to 4.2.8p9 or later, or 4.3.92 or later, using your vendor's packaged fix when available.
• Inventory hosts and appliances that embed or package NTP, then verify the installed version against the fixed release line.
• Apply downstream OS/vendor security updates for affected packaged builds, including the distributions referenced in the source corpus.
• Prioritize internet-exposed or mission-critical time servers for remediation and validate service stability after patching.

Evidence notes

This debrief is grounded in the official CVE/NVD record and the linked downstream package advisories. The CVE record published on 2017-01-30 provides the affected version ranges, description, CVSS vector, and CWE mapping. Reference advisories in 2016 from Fedora and openSUSE show active downstream remediation. The corpus does not provide exploit code, confirmed exploitation, or ransomware linkage.

Official resources