GHSA-9PGC-3CCV-5297 zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service

Impact DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer RFC 1035 §4.1.4. Pointer cycles and label counts were capped, but the chain length of unique forward pointers was not. A single 3 kB mDNS packet carrying 1500 chained pointers drives the recursion past CPython'...

zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service

Impact DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer RFC 1035 §4.1.4. Pointer cycles and label counts were capped, but the chain length of unique forward pointers was not. A single 3 kB mDNS packet carrying 1500 chained pointers drives the recursion past CPython'...

Uncontrolled Recursion

Overview zeroconf is a Pure Python Multicast DNS Service Discovery Library Bonjour/Avahi compatible Affected versions of this package are vulnerable to Uncontrolled Recursion via the DNSIncoming.decodelabelsatoffset function. An attacker can cause excessive CPU consumption and log flooding by...