VDB-95317 · CVE-2016-7426 · BID 94451

ntpd up to 4.2.8p8 Rate Limit resource management

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.

A vulnerability was found in ntpd up to 4.2.8p8 (Network Management Software). It has been declared as problematic. Affected by this vulnerability is an unknown code block of the component Rate Limit Handler. The manipulation with an unknown input leads to a resource management vulnerability. The CWE definition for the vulnerability is CWE-399. As an impact it is known to affect availability.

The bug was discovered 11/21/2016. The weakness was disclosed 01/13/2017 by Miroslav Lichvar with Red Hat (Website). The advisory is shared at nwtime.org. This vulnerability is known as CVE-2016-7426 since 09/09/2016. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

The vulnerability was handled as a non-public zero-day exploit for at least 16 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 95616 (Fedora 23 : ntp (2016-e8a8561ee7)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context local. The commercial vulnerability scanner Qualys is able to test this issue with plugin 371402 (Cisco UCS 6200 Series Fabric Interconnects Multiple Vulnerabilities in Network Time Protocol Daemon (CSCvc23476)).

Upgrading to version 4.2.8p9 eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (95616). The entries 93745, 95318, 95319 and 95320 are pretty similar.





  • open-source

CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍



VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍


Class: Resource management
CWE: CWE-399 / CWE-404
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 95616
Nessus Name: Fedora 23 : ntp (2016-e8a8561ee7)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 71151
OpenVAS Name: NTP.org ntp DoS Vulnerability
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: ntpd 4.2.8p9


09/09/2016 🔍
11/21/2016 +73 days 🔍
11/21/2016 +0 days 🔍
12/07/2016 +16 days 🔍
12/08/2016 +1 days 🔍
01/13/2017 +36 days 🔍
01/13/2017 +0 days 🔍
01/15/2017 +2 days 🔍
10/28/2022 +2112 days 🔍


Advisory: FEDORA-2016-e8a8561ee7
Researcher: Miroslav Lichvar
Organization: Red Hat
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2016-7426 (🔍)

SecurityTracker: 1037354
SecurityFocus: 94451 - NTP CVE-2016-7426 Local Denial of Service Vulnerability
OSVDB: - CVE-2016-7426 - NTP - Denial of Service Issue

See also: 🔍


Created: 01/15/2017 10:37 AM
Updated: 10/28/2022 04:04 PM
Changes: 01/15/2017 10:37 AM (74), 08/19/2020 11:10 AM (9), 10/28/2022 03:58 PM (4), 10/28/2022 04:04 PM (1)
Complete: 🔍


No comments yet. Languages: en.

Please log in to comment.

Interested in the pricing of exploits?

See the underground prices here!