BREW-HOMEASSISTANT-CLI-C… (GHSA-9663-MQMP-P9MM)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:56 – Updated: 2026-09-17 17:53 – Source websiteImpact
AsyncListener.handle_query_or_defer retained every truncated (TC-bit) incoming query in self._deferred[addr] and armed a per-addr timer in self._timers[addr] that flushed the reassembled query within ~500 ms (RFC 6762 §18.5). Neither the per-addr list nor the number of distinct addr keys was capped, and the dedup check (for incoming in reversed(deferred): if incoming.data == msg.data) ran O(N) over the per-addr list on every arrival.
Any unauthenticated host on the local link (UDP/5353, 224.0.0.251 / ff02::fb) can stream byte-distinct TC-flagged mDNS queries — each up to _MAX_MSG_ABSOLUTE = 8966 bytes, with DNSIncoming retaining the raw data buffer plus parsed-record state. Trivially spoofed source IPs multiply the effect across _deferred / _timers, and the O(N) data compare burns CPU quadratically as each per-addr queue grows. On memory-constrained deployments (Home Assistant on Raspberry-Pi-class hardware is the canonical victim) sustained traffic OOM-kills the process; under lighter load, the per-arrival scan and event-loop scheduler starvation break unrelated zeroconf consumers (discovery, registration, ServiceBrowser callbacks).
Patches
Fixed in zeroconf 0.149.12 (PR #1751). Upgrade to >= 0.149.12.
Workarounds
There is no in-process workaround; upgrading is the fix. Otherwise, restrict mDNS (UDP/5353) to trusted Layer-2 segments via AP client isolation, guest-network separation, or host firewall rules.
Resources
- PR #1751, fix
- RFC 6762 §18.5, CWE-400
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "zeroconf",
"resource_purl": "pkg:pypi/zeroconf@0.150.0",
"upstream_fixed_in": "0.149.12"
},
"package": {
"ecosystem": "Homebrew",
"name": "homeassistant-cli",
"purl": "pkg:brew/homeassistant-cli"
},
"ranges": [
{
"events": [
{
"introduced": "0.5.0"
},
{
"fixed": "1.0.0_3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/zeroconf@0.150.0",
"name": "zeroconf",
"resource": "zeroconf",
"strategy": "registry",
"subject_version": "0.150.0"
}
]
},
"details": "### Impact\n\n`AsyncListener.handle_query_or_defer` retained every truncated (TC-bit) incoming query in `self._deferred[addr]` and armed a per-addr timer in `self._timers[addr]` that flushed the reassembled query within ~500 ms (RFC 6762 \u00a718.5). Neither the per-addr list nor the number of distinct `addr` keys was capped, and the dedup check (`for incoming in reversed(deferred): if incoming.data == msg.data`) ran O(N) over the per-addr list on every arrival.\n\nAny unauthenticated host on the local link (UDP/5353, `224.0.0.251` / `ff02::fb`) can stream byte-distinct TC-flagged mDNS queries \u2014 each up to `_MAX_MSG_ABSOLUTE = 8966` bytes, with `DNSIncoming` retaining the raw `data` buffer plus parsed-record state. Trivially spoofed source IPs multiply the effect across `_deferred` / `_timers`, and the O(N) data compare burns CPU quadratically as each per-addr queue grows. On memory-constrained deployments (Home Assistant on Raspberry-Pi-class hardware is the canonical victim) sustained traffic OOM-kills the process; under lighter load, the per-arrival scan and event-loop scheduler starvation break unrelated zeroconf consumers (discovery, registration, ServiceBrowser callbacks).\n\n### Patches\n\nFixed in `zeroconf` 0.149.12 ([PR #1751](https://github.com/python-zeroconf/python-zeroconf/pull/1751)). Upgrade to `\u003e= 0.149.12`.\n\n### Workarounds\n\nThere is no in-process workaround; upgrading is the fix. Otherwise, restrict mDNS (UDP/5353) to trusted Layer-2 segments via AP client isolation, guest-network separation, or host firewall rules.\n\n### Resources\n\n- [PR #1751](https://github.com/python-zeroconf/python-zeroconf/pull/1751), fix\n- [RFC 6762 \u00a718.5](https://www.rfc-editor.org/rfc/rfc6762#section-18.5), [CWE-400](https://cwe.mitre.org/data/definitions/400.html)",
"id": "BREW-homeassistant-cli-CVE-2026-48045",
"modified": "2026-09-17T17:53:52Z",
"published": "2026-08-13T16:56:27Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9663-mqmp-p9mm"
},
{
"type": "WEB",
"url": "https://github.com/python-zeroconf/python-zeroconf/pull/1751"
},
{
"type": "WEB",
"url": "https://github.com/python-zeroconf/python-zeroconf/commit/b22c8ff19c66c68907d220a4823c0950f4fa93f7"
},
{
"type": "PACKAGE",
"url": "https://github.com/python-zeroconf/python-zeroconf"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "python-zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source flood",
"upstream": [
"GHSA-9663-mqmp-p9mm",
"CVE-2026-48045",
"PYSEC-2026-3435"
]
}
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