High [CVE-2026-11605] Unnecessary validation of DNSSEC signed records
This high-severity Red Hat Linux advisory covers CVE-2026-11605 affecting Red Hat Hardened Images.
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Summary
The 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.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-400.
Affected Red Hat products: Red Hat Hardened Images. Under investigation: Red Hat Enterprise Linux 9.
Red Hat fixing advisory: RHSA-2026:42853.
- 9.20.0
- 9.20.24
- 9.21.0
- 9.21.23
- 9.20.9
Official advisory · high-confidence parse· fetched 8 days ago·verify at source
- bind-main-9.18.50-22.hum1
- RHSA-2026:42853
Official advisory · high-confidence parse· fetched 8 days ago·verify at source
Mitigation
Upgrade to a fixed release: bind-main-9.18.50-22.hum1, RHSA-2026:42853. 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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