A vulnerability in dnspython's dns.name.from_wire_parser() function can cause excessive CPU usage when processing maliciously crafted DNS messages. This can degrade or deny service to applications using dnspython for DNS name decompression. The issue affects FastAPI versions from 0.111.0 up to but not including 0.143.1. The vulnerability is fixed in dnspython 2.9.0 and FastAPI 0.143.1. No workarounds are known.