CVE-2026-3593 is a high-severity heap use-after-free vulnerability disclosed on May 20, 2026, in the DNS-over-HTTPS implementation of BIND 9, affecting BIND 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and the supported preview 9.20.9-S1 through 9.20.22-S1. ISC says crafted HTTP/2 traffic...