CVE-2026-47184

MEDIUM 6.5

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

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-770
Vendor	python-zeroconf
Product	python-zeroconf
Published	Jul 17, 2026

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CVSS v3 Breakdown

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

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

python-zeroconf / python-zeroconf

< 0.149.7

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-rfg2-pjw2-56x2 github.com: https://github.com/python-zeroconf/python-zeroconf/issues/1715 github.com: https://github.com/python-zeroconf/python-zeroconf/pull/1718 github.com: https://github.com/python-zeroconf/python-zeroconf/commit/0ad3f37b5b852b8f614d322283d148efb2cef6e4 github.com: https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.7