High [CVE-2026-11331] Potential wildcard CNAME RPZ policy bypass
This high-severity Red Hat Linux advisory covers CVE-2026-11331 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions.
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Summary
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.
A flaw was found in BIND 9, a widely used Domain Name System (DNS) software. A remote attacker could exploit this by sending specially crafted, excessively long DNS queries.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N). Weakness: CWE-20.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.6 Extended Update Support; Red Hat Hardened Images; Red Hat OpenShift Container Platform 4.
Red Hat lists Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected. Red Hat fixing advisory: RHSA-2026:55437, RHSA-2026:54509, RHSA-2026:54510, RHSA-2026:55442, RHSA-2026:57189, RHSA-2026:55441, RHSA-2026:54071.
- 9.16.0
- 9.18.50
- 9.20.0
- 9.20.24
- 9.21.0
- 9.21.23
- 9.16.8
- 9.20.9
Official advisory · high-confidence parse· fetched 8 days ago·verify at source
- bind-32:9.18.33-15.el10_2.10
- bind9.16-32:9.16.23-0.22.el8_10.12
- bind-32:9.16.23-40.el9_8.8
- bind9.18-32:9.18.29-14.el9_8.8
- bind-32:9.16.23-18.el9_4.12
- bind-32:9.16.23-31.el9_6.4
- bind-main-9.20.26-0.1.hum1
- RHSA-2026:55437
- RHSA-2026:54509
- RHSA-2026:54510
- RHSA-2026:55442
- RHSA-2026:57189
- RHSA-2026:55441
- RHSA-2026:54071
Official advisory · high-confidence parse· fetched 8 days ago·verify at source
Mitigation
Upgrade to a fixed release: bind-32:9.18.33-15.el10_2.10, bind9.16-32:9.16.23-0.22.el8_10.12, bind-32:9.16.23-40.el9_8.8, bind9.18-32:9.18.29-14.el9_8.8, bind-32:9.16.23-18.el9_4.12, bind-32:9.16.23-31.el9_6.4. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 8 days ago·verify at source
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