ISC

This vulnerability affects BIND 9 resolver (`named`) and can lead to unexpected program termination (denial of service). The issue occurs when the resolver receives specific, delayed, or out-of-order responses to queries for CNAME or DNAME and A records. Specifically, if an authoritative server delays a DNAME or self-referential CNAME response while providing an A record, the `named` process may crash.

A DNSSEC validating resolver, specifically BIND 9 versions within the ranges 9.11.0-9.18.50, 9.20.0-9.20.24, 9.21.0-9.21.23, and their S1 variants, is vulnerable to a denial-of-service attack where an attacker can launch a random subdomain attack against a DNSSEC-signed zone by sending queries faster than the resolver can perform validation, leading to runaway memory usage and potentially exceeding configured limits by orders of magnitude.

An attacker can exploit CVE-2026-11331, a flaw in ISC BIND 9's RPZ (Response Policy Zone) processing, by crafting long query names to trigger a mishandled NAMETOOLONG error, leading to either a bypass of RPZ rules or a denial of service due to an unexpected exit of the BIND 9 software.

BIND servers configured for TKEY-based authentication using GSS-API tokens are susceptible to excessive memory consumption upon receiving and processing crafted packets, impacting availability.

A race condition in ISC BIND can lead to a use-after-free vulnerability (CVE-2026-5947) when handling SIG(0) signed DNS messages, potentially leading to undefined behavior.

Multiple flaws in BIND 9's `named` component, specifically versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1, can be exploited by sending specially crafted DNS requests with non-`IN` CLASS or meta-classes, leading to assertion failures and potential denial-of-service.