An 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.
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.
Advisories
No advisories yet.
Fixes
Solution
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.
Workaround
No workarounds known.
References
History
Wed, 22 Jul 2026 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | An 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. | |
| Title | Potential wildcard CNAME RPZ policy bypass | |
| First Time appeared |
Isc
Isc bind |
|
| Weaknesses | CWE-790 | |
| CPEs | cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Isc
Isc bind |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: isc
Published:
Updated: 2026-07-22T18:54:17.064Z
Reserved: 2026-06-05T07:03:42.361Z
Link: CVE-2026-11331
No data.
No data.
No data.
OpenCVE Enrichment
No data.
Weaknesses