Unnecessary validation of DNSSEC signed records

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-11605
StatePUBLISHED
Assignerisc
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-22 15:16:51 UTC
Updated2026-07-22 20:33:11 UTC
DescriptionThe issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-408 | CWE-408 CWE-408 Incorrect Behavior Order - Early Amplification

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA ISC BIND 9 affected 9.20.0 9.20.24 custom Not specified
CNA ISC BIND 9 affected 9.21.0 9.21.23 custom Not specified
CNA ISC BIND 9 affected 9.20.9-S1 9.20.24-S1 custom Not specified

References

ReferenceSourceLinkTags
kb.isc.org/docs/cve-2026-11605 [email protected] kb.isc.org
downloads.isc.org/isc/bind9/9.21.24 [email protected] downloads.isc.org
downloads.isc.org/isc/bind9/9.20.26 [email protected] downloads.isc.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.26, 9.21.24, or 9.20.26-S1.

Workarounds

CNA: No workarounds known.

Exploits

CNA: This flaw was discovered in internal testing. We are not aware of any active exploits.

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