ISC BIND 9 up to 9.20.27-S1 named input validation

CVSS Meta Temp Score
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CTI Interest Score
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7.3$0-$5k0.44

Summaryinfo

A vulnerability classified as critical has been found in ISC BIND 9 up to 9.18.50/9.20.27/9.21.25/9.18.50-S1/9.20.27-S1. Affected is an unknown function of the component named. This manipulation causes input validation. This vulnerability appears as CVE-2026-19667. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in ISC BIND 9 up to 9.18.50/9.20.27/9.21.25/9.18.50-S1/9.20.27-S1. It has been declared as critical. Affected by this vulnerability is some unknown processing of the component named. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability. The summary by CVE is:

If an attacker-controlled authoritative server can produce a negative answer that is exactly 65536 bytes, then a flaw in `named` results in a negative cache entry of 0 bytes. When this entry is subsequently read, `named` aborts. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

It is possible to read the advisory at kb.isc.org. This vulnerability is known as CVE-2026-19667 since 08/12/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/16/2026).

Upgrading to version 9.18.50-S1, 9.20.27-S1 or 9.21.25 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (isc): 🔒

CVSSv2info

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

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: BIND 9 9.18.50-S1/9.20.27-S1/9.21.25

Timelineinfo

08/12/2026 CVE reserved
09/16/2026 +35 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: isc.org

Advisory: kb.isc.org
Status: Confirmed

CVE: CVE-2026-19667 (🔒)
GCVE (CVE): GCVE-0-2026-19667
GCVE (VulDB): GCVE-100-405943

Entryinfo

Created: 09/16/2026 16:26
Changes: 09/16/2026 16:26 (64)
Complete: 🔍
Cache ID: 216::103

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