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Fencer Intel
medium 5.3

CVE-2016-2517 json

NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leve…

published 2017-01-30 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3595

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
8.8%
EPSS 8.8% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leveraging knowledge of the controlkey or requestkey and sending a crafted packet to ntpd, which changes the value of trustedkey, controlkey, or requestkey. NOTE: this vulnerability exists because of a CVE-2016-2516 regression.

Patch / fix

  • ntp Debian 11 1:4.2.8p7+dfsg-1

debian advisories DEBIAN-CVE-2016-2517

  • ntp SLES for SAP 12, SLES 12, SLED 12 4.2.8p8-46.8.1
  • ntp SLES 11 SP3-TERADATA, SLES 11 SP3-LTSS, SLES 11 SP2-LTSS +3 more 4.2.8p7-44.1
  • ntp SLES 12 SP1, SLES 11 SP4, SLED 12 SP1 +2 more 4.2.8p7-11.1

suse advisories SUSE-SU-2016:1568-1SUSE-SU-2016:1471-1SUSE-SU-2016:1291-1SUSE-SU-2016:1278-1

  • ntp openSUSE Tumbleweed 4.2.8p9-1.1

opensuse advisories openSUSE-SU-2024:10181-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-2517 updated cvss 2.1

ntp: certain remote configuration values not properly validated

  • Red Hat Enterprise Linux 5 ntp Red Hat Enterprise Linux 6 ntp, ntpdate, ntp-perl Red Hat Enterprise Linux 7 ntp, sntp, ntpdate, ntp-perl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

8.82% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:N/AC:H/Au:S/C:N/I:N/A:C

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.