# CVE-2026-48045: python-zeroconf: Zeroconf is a pure Python implementation of multicast DNS service discovery

CVE-2026-48045 is fixed in python-zeroconf on 1 platform, first by OPENSUSE-SU-2026:21175-1, released June 30, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-48045
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 30, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-zeroconf Debian 14 | 0.149.16-1 | [DEBIAN-CVE-2026-48045](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48045.md) | Jul 18, 2026 |
| Linux | python-zeroconf opensuse-leap 16.0 | 0.136.0-bp160.2.1 | [OPENSUSE-SU-2026:21175-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21175-1.md) | Jun 30, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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