CVE-2026-48045: Paulsm Zeroconf

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.12, AsyncListener.handle_query_or_defer retained every truncated TC-bit incoming query, each up to _MAX_MSG_ABSOLUTE = 8966 bytes, in self._deferred[addr] and armed a per-address timer in self._timers[addr] without capping the per-address list or distinct addr keys, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to spoof sources, grow _deferred and _timers, and cause memory exhaustion and quadratic CPU burn. This issue is fixed in version 0.149.12.

Affected products

• Paulsm Zeroconf: before 0.149.12 (fixed in 0.149.12)

Published 2026-07-17. Last modified 2026-08-17.