Potential wildcard CNAME RPZ policy bypass

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-11331
StatePUBLISHED
Assignerisc
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-22 15:16:51 UTC
Updated2026-07-22 20:33:11 UTC
DescriptionAn attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can craft query names long enough to trigger a NAMETOOLONG error condition during RPZ processing. This is not handled correctly and may lead to defeating the RPZ rule. It also may lead to an unexpected exit of the BIND 9 software. This issue affects BIND 9 versions 9.16.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.16.8-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:H/I:N/A:N

Problem Types: CWE-790 | CWE-790 CWE-790 Improper Filtering of Special Elements

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

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA ISC BIND 9 affected 9.16.0 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 9.21.0 9.21.23 custom Not specified
CNA ISC BIND 9 affected 9.16.8-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-2026-11331 [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

Vendor Comments And Credit

Discovery Credit

CNA: ISC would like to thank Laith Mash'al (0xmshal) 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, 9.21.24, or 9.20.26-S1.

Workarounds

CNA: No workarounds known.

Exploits

CNA: We are not aware of any active exploits.

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