CVE-2026-47180

MEDIUM

Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service

Title source: cna

Description

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.

References (4)

Core 4

Core References

X_Refsource_Confirm x_refsource_confirm

https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9pgc-3ccv-5297

X_Refsource_Misc x_refsource_misc

https://github.com/python-zeroconf/python-zeroconf/pull/1719

X_Refsource_Misc x_refsource_misc

https://github.com/python-zeroconf/python-zeroconf/commit/f9e23592137f30fdf7ef710dba065da31c79b1cf

View Writeup ZIP pw:eip

X_Refsource_Misc x_refsource_misc

https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.5

Scores

CVSS v3 6.5

EPSS 0.0023

EPSS Percentile 13.9%

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-674

Status published

Products (1)

python-zeroconf/python-zeroconf < 0.149.5

Published Jul 17, 2026

Tracked Since Jul 18, 2026