Update to 9.18.49 (#2480121)

Security Fixes:

• Limit resolver server list size. (CVE-2026-3592)
• Fix GSS-API resource leak. (CVE-2026-3039)
• Disable recursion, UPDATE, and NOTIFY for non-IN views. (CVE-2026-5946)
• Avoid unbounded recursion loop. (CVE-2026-5950)
• Fix outgoing zone transfers' quota issue.

Feature Changes:

• Fix CPU spikes and slow queries when cache approaches memory limit.

Bug Fixes:

• Fix named crash when processing SIG records in dynamic updates.
• Fix rndc modzone behavior for a zone in named.conf.
• Fix zone verification of NSEC3 signed zones.
• Prevent a crash when using both dns64 and filter-aaaa.
• Fixed an assertion failure when processing catalog zones.
• Prevent malicious DNSSEC zones from exhausting validator CPU.
• Fix rndc-confgen aborting on HMAC-SHA-384/512 keys above 512 bits.
• Prevent crafted queries from degrading RRL performance.
• Fix a bug in allow-query/allow-transfer catalog zone custom properties.
• Fix a memory leak issue in catalog zones.
• Fix suppressed missing-glue check in named-checkzone.
• Reject record sets too large to serve in DNS.

Source: https://downloads.isc.org/isc/bind9/9.18.49/doc/arm/html/notes.html#notes-for-bind-9-18-49