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PatchSiren cyber security CVE debrief

CVE-2016-9310 Ntp CVE debrief

CVE-2016-9310 affects ntpd control mode (mode 6) handling in NTP before 4.2.8p9. According to the CVE description, a remote attacker could send a crafted control mode packet to set or unset traps. The supplied NVD data rates the issue as CVSS 3.0 6.5 MEDIUM, with network access required but no privileges or user interaction.

Vendor
Ntp
Product
Unknown
CVSS
MEDIUM 6.5
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

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2016-9310 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2016-9310

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2016-9310 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2016-9310

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.