medium6.5
CVE-2026-48045
python-zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source flood
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | zeroconf | < 0.149.12 | 0.149.12 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Paulsm | Zeroconf | before 0.149.12 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-9663-mqmp-p9mm
- https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9663-mqmp-p9mm
- https://github.com/python-zeroconf/python-zeroconf/pull/1751
- https://github.com/python-zeroconf/python-zeroconf/commit/b22c8ff19c66c68907d220a4823c0950f4fa93f7
- https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.12