Record ordering based unexpected exit with CNAME or DNAME

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-12617
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 unexpected program termination based on ordering and/or specific content in responses to queries for CNAME or DNAME, and A records. Specifically, if a client queries for a DNAME and A record below the DNAME to the resolver, and the authoritative server responds positively to the A query but delays the DNAME response and later responds negatively, `named` may quit unexpectedly. Or, if a client queries for a CNAME and A record for the same name to the resolver, and the authoritative server responds positively to the A query but delays the CNAME response and later responds with a self-referential CNAME, the same failure may occur. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.18.11-S1 through 9.18.50-S1, 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-617 | CWE-617 CWE-617 Reachable Assertion

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 9.18.0 9.18.50 custom Not specified
CNA ISC BIND 9 affected 9.20.0 9.20.24 custom Not specified
CNA ISC BIND 9 affected 9.18.11-S1 9.18.50-S1 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-2026-12617 [email protected] kb.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

Vendor Comments And Credit

Discovery Credit

CNA: ISC would like to thank Qifan Zhang of Palo Alto Networks for bringing this vulnerability to our attention. (en)

Additional Advisory Data

Solutions

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

Workarounds

CNA: No workarounds known.

Exploits

CNA: We are not aware of any active exploits.

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