CVE-2026-19667

Name of the Vulnerable Software and Affected Versions BIND 9 versions 9.11.0 through 9.18.50 BIND 9 versions 9.20.0 through 9.20.27 BIND 9 versions 9.21.0 through 9.21.25 BIND 9 versions 9.11.3-S1 through 9.18.50-S1 BIND 9 versions 9.20.9-S1 through 9.20.27-S1

Description A flaw in named occurs when an attacker-controlled authoritative server produces a negative answer of exactly 65536 bytes. This leads to a negative cache entry of 0 bytes due to a 16-bit length truncation in the dns ncache add() function. When this entry is subsequently read, named aborts, resulting in a remote assertion failure.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.