Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.init, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb). This issue is fixed in version 0.149.5.
Exploitability
AV:AAC:LPR:NUI:NScope
S:UImpact
C:NI:NA:H6.5/CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HOther