SIG(0)

BIND DNS Servers Receive Patches for 14 Vulnerabilities Including High-Severity DoS Flaws

The Internet Systems Consortium has released BIND 9 updates that address 14 vulnerabilities across multiple versions of the widely used DNS server software. Seven of the issues received a CVSS score of 7.5 and were rated high severity, while the remaining seven scored between 5.3 and 6.5. The most critical flaw allows an unauthenticated attacker to crash the named process with a single malformed SIG(0) request over DNS over HTTPS. Additional vulnerabilities enable cache poisoning through forged NXDOMAIN responses, downgraded secure delegations, and acceptance of unsigned answers, as well as resource exhaustion via uncontrolled cache growth and excessive CPU consumption. Affected releases span BIND 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, and 9.21.0 through 9.21.25. No workarounds exist, making immediate upgrades to versions 9.20.29, 9.21.26, or 9.20.29-S1 the only mitigation. The ISC reports no known exploitation in the wild and none of the flaws appear in CISA’s Known Exploited Vulnerabilities catalog.