Description
An issue was discovered in Ruby 4 before 4.0.5. A race condition leading to a use-after-free in the pthread-based getaddrinfo timeout handler (rb_getaddrinfo in ext/socket/raddrinfo.c) allows a remote attacker who can delay DNS responses near the user-specified timeout to crash a Ruby process that calls Addrinfo.getaddrinfo(..., timeout:) or Socket.tcp(..., resolv_timeout:). Memory-corruption-based exploitation is theoretically possible. The attack could, for example, be carried out through a crafted authoritative DNS server or recursive resolver.
Problem types
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Product status
4.0.0 (semver) before 4.0.5
References
www.ruby-lang.org/.../2026/05/20/getaddrinfo-cve-2026-46727/