BIND 9 CVE-2026-1519: The NSEC3 DoS Vulnerability Putting DNS Resolvers at Risk
On March 25, 2026, the Internet Systems Consortium (ISC) released patches for three vulnerabilities in BIND 9, the most widely deployed DNS server software in the world. The headline flaw — CVE-2026-1519 — carries a CVSS score of 7.5 and is remotely exploitable with no authentication required. An attacker who controls a maliciously crafted DNS zone can trigger the vulnerability by forcing a BIND resolver to process excessive NSEC3 iterations during DNSSEC validation of an insecure delegation.