CVE-2025-40775

DNS message with invalid TSIG causes an assertion failure

Published May 21, 2025 CVSS 3.1 · 7.5 High EPSS 15.4% KEV · Not listed
Description
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.

Remediation

Vendor Solution

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


Vendor Workaround

No workarounds known.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-16006 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.
Ubuntu USN Ubuntu USN USN-7526-1 Bind vulnerability
History
Type Values Removed Values Added
Metrics epss

{'score': 0.00016}

epss

{'score': 0.0001}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title DNS message with invalid TSIG causes an assertion failure
Weaknesses CWE-232
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
isc
Published
Updated
May 23, 2025, 1:11 PM
Reserved
Apr 16, 2025, 8:44 AM
Status
Deferred
Published
May 21, 2025, 1:16 PM
Modified
Jun 17, 2026, 9:22 AM
Severity
Important
Public date
May 21, 2025, 12:00 AM