Medium 6.5Published Jul 17, 2026

CVE-2026-48045Zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source flood

Updated under an hour ago (Oct 26, 2026, 5:00 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.12, AsyncListener.handle_query_or_defer retained every truncated TC-bit incoming query, each up to _MAX_MSG_ABSOLUTE = 8966 bytes, in self._deferred[addr] and armed a per-address timer in self._timers[addr] without capping the per-address list or distinct addr keys, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to spoof sources, grow _deferred and _timers, and cause memory exhaustion and quadratic CPU burn. This issue is fixed in version 0.149.12.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

python-zeroconf python-zeroconf python_zeroconf:python_zeroconf (from the name)	before 0.149.12	CNA record
paulsm zeroconf paulsm:zeroconf	before 0.149.12	NVD

References

References

https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9663-mqmp-p9mm	x-refsource-confirm, vendor-advisory, patch
https://github.com/python-zeroconf/python-zeroconf/pull/1751	x-refsource-misc, issue-tracking, patch
https://github.com/python-zeroconf/python-zeroconf/commit/b22c8ff19c66c68907d220a4823c0950f4fa93f7	x-refsource-misc, patch
https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.12	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.