CVE-2026-47180 | Zeroconf is a pure Python implementation of multicast DNS se… | CVSS 6.5 MEDIUM

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.

Metadata

CVE ID: CVE-2026-47180
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-05-18 22:07 UTC
Published: 2026-07-17 18:21 UTC
Last updated: 2026-07-17 19:21 UTC
Primary CWE: CWE-674
CWE-674: Uncontrolled Recursion
Vendor / Product: python-zeroconf / python-zeroconf
Sources: cve.org · NVD

Severity & Metrics

6.5 MEDIUM CVSS 3.1

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
python-zeroconf	python-zeroconf	—	< 0.149.5

Weakness (CWE)

CWE	Source	Description
CWE-674	cna	CWE-674: Uncontrolled Recursion

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.5	MEDIUM	3.1	cna	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (4)

https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9pgc-3ccv-5297 https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9pgc-3ccv-5297
https://github.com/python-zeroconf/python-zeroconf/pull/1719 https://github.com/python-zeroconf/python-zeroconf/pull/1719
https://github.com/python-zeroconf/python-zeroconf/commit/f9e23592137f30fdf7ef710dba065da31c79b1cf https://github.com/python-zeroconf/python-zeroconf/commit/f9e23592137f30fdf7ef710dba065da31c79b1cf
https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.5 https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.5