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NVD / CVE Program· CNA mitre

CVE-2016-2516: NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by…

MediumCVSS 5.3 · v3.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 8.9% (FIRST EPSS); higher than 95.3% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: ntp (Debian:11) 1:4.2.8p7+dfsg-1; ntp (Debian:7) 1:4.2.6.p5+dfsg-2+deb7u7; ntp (Debian:8) 1:4.2.6.p5+dfsg-7+deb8u2.

Low priority for now. Upgrade to ntp (Debian:11) 1:4.2.8p7+dfsg-1; ntp (Debian:7) 1:4.2.6.p5+dfsg-2+deb7u7; ntp (Debian:8) 1:4.2.6.p5+dfsg-7+deb8u2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by using the same IP address multiple times in an unconfig directive.

Published
Jan 30, 2017
Updated
Jun 16, 2026
EPSS
8.9% · 95th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
3 / 30 · 8.9%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2016-2516

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ntpntp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ntp ntpup to 4.2.8 inclusive
  • ntp ntp4.3.0
  • ntp ntp4.3.1
  • ntp ntp4.3.10
  • ntp ntp4.3.11
  • ntp ntp4.3.12
  • ntp ntp4.3.13
  • ntp ntp4.3.14
+12 more rows
  • ntp ntp4.3.15
  • ntp ntp4.3.16
  • ntp ntp4.3.17
  • ntp ntp4.3.18
  • ntp ntp4.3.19
  • ntp ntp4.3.2
  • ntp ntp4.3.20
  • ntp ntp4.3.21
  • ntp ntp4.3.22
  • ntp ntp4.3.23
  • ntp ntp4.3.24
  • ntp ntp4.3.25

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:11ntpbefore 1:4.2.8p7+dfsg-11:4.2.8p7+dfsg-1
Debian:7ntpbefore 1:4.2.6.p5+dfsg-2+deb7u71:4.2.6.p5+dfsg-2+deb7u7
Debian:8ntpbefore 1:4.2.6.p5+dfsg-7+deb8u21:4.2.6.p5+dfsg-7+deb8u2
SUSE:Linux Enterprise Desktop 12ntpbefore 4.2.8p8-46.8.14.2.8p8-46.8.1
SUSE:Linux Enterprise Server 11 SP4ntpbefore 4.2.8p7-11.14.2.8p7-11.1
SUSE:OpenStack Cloud 5ntpbefore 4.2.8p7-44.14.2.8p7-44.1

Same product

ntp: all records

Other highest-scoring records for the same primary product.

  • CVE-2015-7871Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass authentication.
    64This week
  • CVE-2014-9295Multiple stack-based buffer overflows in ntpd in NTP before 4.2.8 allow remote attackers to execute arbitrary code via a crafted packet…
    54Plan
  • CVE-2013-5211The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic…
    49Plan

Published before and after this one in the same product

  • ← EarlierCVE-2015-8140Jan 30, 2017 · The ntpq protocol in NTP before 4.2.8p7 allows remote attackers to conduct replay attacks by sniffing the network.
    20Monitor
  • ← EarlierCVE-2015-8158Jan 30, 2017 · The getresponse function in ntpq in NTP versions before 4.2.8p9 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of…
    25Monitor
  • Later →CVE-2016-2517Jan 30, 2017 · 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…
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:ntp1:4.2.8p7+dfsg-1 · Debian:11Package registry (OSV)
suse:ntp4.2.8p7-11.1 · SUSE:Linux Enterprise Server 11 SP4Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records