CVE-2026-48045
Zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source 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 0.149.12, 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.
| CWE | CWE-770 |
| Vendor | python-zeroconf |
| Product | python-zeroconf |
| Published | Jul 17, 2026 |
| Last Updated | 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
< 0.149.12
References
github.com: https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9663-mqmp-p9mm github.com: https://github.com/python-zeroconf/python-zeroconf/pull/1751 github.com: https://github.com/python-zeroconf/python-zeroconf/commit/b22c8ff19c66c68907d220a4823c0950f4fa93f7 github.com: https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.12