CVE-2026-47184

MEDIUM

Zeroconf: Unbounded DNS record cache allows LAN-local memory exhaustion via multicast flood

Title source: cna
STIX 2.1

Description

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.7, DNSCache._async_add inserted every response record into cache, _expirations, _expire_heap, and service_cache without a cap, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to multicast valid mDNS responses with unique names and cause memory exhaustion, slower cache lookups, slower async_expire passes, and broken discovery, registration, and ServiceBrowser callbacks. This issue is fixed in version 0.149.7.

Scores

CVSS v3 6.5
EPSS 0.0024
EPSS Percentile 15.4%
Attack Vector ADJACENT_NETWORK
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-770
Status published
Products (1)
python-zeroconf/python-zeroconf < 0.149.7
Published Jul 17, 2026
Tracked Since Jul 18, 2026