ISC BIND up to 9.20.8/9.21.7 Incoming DNS Protocol Message undefined values

Summaryinfo

A vulnerability marked as problematic has been reported in ISC BIND up to 9.20.8/9.21.7. Affected by this vulnerability is an unknown functionality of the component Incoming DNS Protocol Message Handler. This manipulation causes improper handling of undefined values. The identification of this vulnerability is CVE-2025-40775. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in ISC BIND up to 9.20.8/9.21.7. It has been declared as problematic. Affected by this vulnerability is an unknown code of the component Incoming DNS Protocol Message Handler. The manipulation with an unknown input leads to a improper handling of undefined values vulnerability. The CWE definition for the vulnerability is CWE-232. The product does not handle or incorrectly handles when a value is not defined or supported for the associated parameter, field, or argument name. As an impact it is known to affect availability. The summary by CVE is:

When an incoming DNS protocol message includes a Transaction Signature (TSIG), BIND always checks it. If the TSIG contains an invalid value in the algorithm field, BIND immediately aborts with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.8 and 9.21.0 through 9.21.7.

It is possible to read the advisory at kb.isc.org. This vulnerability is known as CVE-2025-40775 since 04/16/2025. 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 vulnerability scanner Nessus provides a plugin with the ID 237601 (SUSE SLED15 / SLES15 Security Update : bind (SUSE-SU-2025:01787-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 9.20.9 or 9.21.8 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (237601). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Domain Name Software

Vendor

• ISC

Name

• BIND

Version

• 9.20.0
• 9.20.1
• 9.20.2
• 9.20.3
• 9.20.4
• 9.20.5
• 9.20.6
• 9.20.7
• 9.20.8
• 9.21.0
• 9.21.1
• 9.21.2
• 9.21.3
• 9.21.4
• 9.21.5
• 9.21.6
• 9.21.7

License

• open-source

Website

• Vendor: https://www.isc.org/

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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