Vulnerability Database

383,371

Total vulnerabilities in the database

CVE-2016-7426 — ntp / ntp

Uncontrolled Resource Consumption

NTP before 4.2.8p9 rate limits responses received from the configured sources when rate limiting for all associations is enabled, which allows remote attackers to cause a denial of service (prevent responses from the sources) by sending responses with a spoofed source address.

  • Published: Jan 13, 2017
  • Updated: Sep 13, 2026
  • CVE: CVE-2016-7426
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 7.5
  • AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v2:

  • Severity: Medium
  • Score: 4.3
  • AV:N/AC:M/Au:N/C:N/I:N/A:P

CWEs:

Software Affected versions
ntp / ntp >= 4.2.6, < 4.2.8
ntp / ntp >= 4.3.0, < 4.3.94
hpe / hpux-ntp >= b.11.31, < c.4.2.8.2.0
ntp / ntp = 4.2.5-p203
ntp / ntp = 4.2.5-p204
ntp / ntp = 4.2.5-p205
ntp / ntp = 4.2.5-p206
ntp / ntp = 4.2.5-p207
ntp / ntp = 4.2.5-p208
ntp / ntp = 4.2.5-p209
ntp / ntp = 4.2.5-p210
ntp / ntp = 4.2.5-p211
ntp / ntp = 4.2.5-p212
ntp / ntp = 4.2.5-p213
ntp / ntp = 4.2.5-p214
ntp / ntp = 4.2.5-p215
ntp / ntp = 4.2.5-p216
ntp / ntp = 4.2.5-p217
ntp / ntp = 4.2.5-p218
ntp / ntp = 4.2.5-p219
ntp / ntp = 4.2.5-p220
ntp / ntp = 4.2.5-p221
ntp / ntp = 4.2.5-p222
ntp / ntp = 4.2.5-p223
ntp / ntp = 4.2.5-p224
ntp / ntp = 4.2.5-p225
ntp / ntp = 4.2.5-p226
ntp / ntp = 4.2.5-p227
ntp / ntp = 4.2.5-p228
ntp / ntp = 4.2.5-p229
ntp / ntp = 4.2.5-p230
ntp / ntp = 4.2.5-p231_rc1
ntp / ntp = 4.2.5-p232_rc1
ntp / ntp = 4.2.5-p233_rc1
ntp / ntp = 4.2.5-p234_rc1
ntp / ntp = 4.2.5-p235_rc1
ntp / ntp = 4.2.5-p236_rc1
ntp / ntp = 4.2.5-p237_rc1
ntp / ntp = 4.2.5-p238_rc1
ntp / ntp = 4.2.5-p239_rc1
ntp / ntp = 4.2.5-p240_rc1
ntp / ntp = 4.2.5-p241_rc1
ntp / ntp = 4.2.5-p242_rc1
ntp / ntp = 4.2.5-p243_rc1
ntp / ntp = 4.2.5-p244_rc1
ntp / ntp = 4.2.5-p245_rc1
ntp / ntp = 4.2.5-p246_rc1
ntp / ntp = 4.2.5-p247_rc1
ntp / ntp = 4.2.5-p248_rc1
ntp / ntp = 4.2.5-p249_rc1
ntp / ntp = 4.2.5-p250_rc1
ntp / ntp = 4.2.8
ntp / ntp = 4.2.8-p1
ntp / ntp = 4.2.8-p1-beta1
ntp / ntp = 4.2.8-p1-beta2
ntp / ntp = 4.2.8-p1-beta3
ntp / ntp = 4.2.8-p1-beta4
ntp / ntp = 4.2.8-p1-beta5
ntp / ntp = 4.2.8-p1-rc1
ntp / ntp = 4.2.8-p1-rc2
ntp / ntp = 4.2.8-p2
ntp / ntp = 4.2.8-p2-rc1
ntp / ntp = 4.2.8-p2-rc2
ntp / ntp = 4.2.8-p2-rc3
ntp / ntp = 4.2.8-p3
ntp / ntp = 4.2.8-p3-rc1
ntp / ntp = 4.2.8-p3-rc2
ntp / ntp = 4.2.8-p3-rc3
ntp / ntp = 4.2.8-p4
ntp / ntp = 4.2.8-p5
ntp / ntp = 4.2.8-p6
ntp / ntp = 4.2.8-p7
ntp / ntp = 4.2.8-p8
canonical / ubuntu_linux = 12.04
redhat / enterprise_linux_desktop = 6.0
redhat / enterprise_linux_desktop = 7.0
redhat / enterprise_linux_server = 6.0
redhat / enterprise_linux_server = 7.0
redhat / enterprise_linux_server_aus = 7.3
redhat / enterprise_linux_server_aus = 7.4
redhat / enterprise_linux_server_aus = 7.6
redhat / enterprise_linux_server_aus = 7.7
redhat / enterprise_linux_server_eus = 7.3
redhat / enterprise_linux_server_eus = 7.4
redhat / enterprise_linux_server_eus = 7.5
redhat / enterprise_linux_server_eus = 7.6
redhat / enterprise_linux_server_eus = 7.7
redhat / enterprise_linux_server_tus = 7.3
redhat / enterprise_linux_server_tus = 7.6
redhat / enterprise_linux_server_tus = 7.7
redhat / enterprise_linux_workstation = 6.0
redhat / enterprise_linux_workstation = 7.0

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.