CVE-2025-40775: DNS message with invalid TSIG causes an assertion failure

Published May 21, 2025
·
Updated

DNS message with invalid TSIG causes an assertion failure

Other sources

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.

NVD

Affected Software

3 affected componentsFixes available
ISC BIND>=9.20.0<=9.20.8, >=9.21.0<=9.21.7
Microsoft azl3 bind 9.20.5-4
Microsoft azl3 bind 9.20.9-1

Remediation

Information

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.9 or 9.21.8.

Event History

May 21, 2025
CVE Published
via MITRE·12:35 PM
Data Sourced
via MITRE·12:35 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeakness
Jul 11, 2025
Data Sourced
via Microsoft·07:00 AM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·07:00 AM
Affected Software
Updated
via Microsoft·07:00 AM
Affected Software
Updated
via Microsoft·07:00 AM
DescriptionSeverity
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Frequently Asked Questions

1

What is the severity of CVE-2025-40775?

CVE-2025-40775 has a severity rating that indicates a potential for exploitation due to assertion failure.

2

How do I fix CVE-2025-40775?

To fix CVE-2025-40775, you should update BIND to the latest available version beyond 9.20.8 and 9.21.7.

3

Which versions of BIND are affected by CVE-2025-40775?

CVE-2025-40775 affects BIND 9 versions 9.20.0 through 9.20.8 and 9.21.0 through 9.21.7.

4

What impact does CVE-2025-40775 have on system security?

CVE-2025-40775 can lead to a denial of service due to BIND aborting when encountering an invalid TSIG algorithm.

5

Is CVE-2025-40775 a critical vulnerability?

CVE-2025-40775 is considered critical due to the potential for causing service disruptions.

Contact

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