CVE-2016-9444

Exploitation likely. EPSS gives it a 18% chance of exploitation in the next 30 days. A vendor fix is available.

CVSS 3.07.5High EPSS percentile97th18% chance in 30 days CISA KEVNot listedNo confirmed exploitation
No public exploit known FixVendor fixNo build named by the sources

Published 2017-01-12Updated 2026-05-06Sources: CVE.org, NVD

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

Steps

Written by AI from the record

Check whether you run ISC BIND and identify its installed version.
Upgrade BIND 9.9.x to 9.9.9-P5, 9.10.x to 9.10.4-P5, or 9.11.x to 9.11.0-P2 or later.
Restart the BIND service after upgrading and confirm name resolution still works.

Vendor advisory Some work to apply

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

named in ISC BIND 9.x before 9.9.9-P5, 9.10.x before 9.10.4-P5, and 9.11.x before 9.11.0-P2 allows remote attackers to cause a denial of service (assertion failure and daemon exit) via a crafted DS resource record in an answer.

In plain language

Written by AI from the record

If you run ISC BIND older than 9.9.9-P5, 9.10.4-P5, or 9.11.0-P2, update it because an outsider can stop your DNS service.

Remote unauthenticated denial of service in ISC BIND named: a malformed DS record in a DNS answer triggers an assertion failure and daemon exit.

If you're affected

DNS service outage
Website access disruption
Email delivery disruption
Manual service restart

What is it

BIND is software that helps computers find the internet address for a website or service name. This flaw lets someone send a booby-trapped DNS reply that can make that service shut down, like sending a malformed form that causes a reception desk to close until staff reopen it.

Who is affected

This matters to you if you run ISC BIND as a DNS server or resolver. An attacker does not need a login or anyone to click anything; it is only a risk if the server processes DNS responses.

How urgent is it

An attacker can send malformed DNS data over the network to crash the service, so treat this as prompt planned maintenance. It is not listed in CISA's known-exploited catalog and no public exploit code is on record, which supports an amber—not emergency—priority.

What to do — in detail

Confirm exposure by checking the named/BIND version on every DNS server and identifying systems that process DNS answers from other servers.

Upgrade the applicable branch to 9.9.9-P5 for 9.9.x, 9.10.4-P5 for 9.10.x, or 9.11.0-P2 for 9.11.x, or move to a supported later release. Review the ISC advisory and your operating system's package notes before moving between major BIND branches; the findings do not specify any breaking-change details.

If patching is delayed, limit which systems can send DNS traffic to the server and reduce unnecessary exposure of DNS resolvers to untrusted networks. After the upgrade, restart named, verify successful DNS lookups, and investigate unexpected named exits or assertion-failure logs. CISA has not assigned a KEV remediation due date.

Technical context

CVSS v3.0 is 7.5 (High): AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. The issue is CWE-20 input validation: a crafted DS resource record in a DNS answer can trigger an assertion failure and terminate named. It is network-reachable in the default configuration when a vulnerable BIND server processes DNS responses. EPSS predicts 18.3% likelihood (97th percentile) and is falling. CVE-2016-9444 is not in CISA KEV, and no public exploit code is on record.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS97th

CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

18% chance of exploitation activity in the next 30 days, which ranks it in the 97th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

24 events over 3541 days, from the signal feeds we watch.

2026-09-23EPSS band changelow → moderateepss band change
2026-09-21EPSS band changemoderate → lowepss band change
2026-09-06EPSS band change0 → moderateepss band change
2026-09-05EPSS band changemoderate → 0epss band change
2026-08-31EPSS band change0 → moderateepss band change
2026-08-29EPSS band changemoderate → low

Affected products

isccommercial · USaka internet systems consortium
- bindNetworking Infrastructure

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.0 vector

Open in the CVSS calculator

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

Scored 7.5 by NVD.

How it is reached

Attack Vector NetworkExploitable remotely over the network without any special conditions
Attack Complexity LowNo special conditions — the attack can be reliably reproduced
Privileges Required NoneNo authentication required — anyone can exploit this
User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

Confidentiality NoneNo confidentiality impact
Integrity NoneNo integrity impact
Availability HighTotal denial of service — the component is completely unavailable