Dnsmasq Abnormal Termination (CVE-2026-4892)

Detects dnsmasq or its DHCP helper child process terminating abnormally on Linux hosts due to signals like SIGSEGV, SIGABRT, SIGBUS, or SIGILL. This behavior is indicative of a crash, potentially caused by exploitation attempts of vulnerabilities such as CVE-2026-4892, a heap buffer overflow in dnsmasq's helper.c when processing oversized DHCPv6 Client Identifier (CLID) options. This rule fires post-impact, complementing network-side detections.