{"id":"CVE-2026-47183","aliases":["GHSA-phvx-9mgw-67r5","PYSEC-2026-3437"],"title":"zeroconf: Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion","summary":"zeroconf: Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"zeroconf","product":"zeroconf","ecosystem":"pip","affected":["zeroconf < 0.149.6"],"patched":["zeroconf 0.149.6"],"published":"2026-05-29","updated":"2026-07-13","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-phvx-9mgw-67r5","references":[{"url":"https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-phvx-9mgw-67r5"},{"url":"https://github.com/python-zeroconf/python-zeroconf/issues/1714"},{"url":"https://github.com/python-zeroconf/python-zeroconf/pull/1717"},{"url":"https://github.com/python-zeroconf/python-zeroconf"}],"tags":["osv","pip"],"ingestedAt":"2026-07-13T18:58:01.488Z","epss":0.00389,"epssPercentile":0.32861,"slug":"CVE-2026-47183","body":"## Overview\n\n### Impact\n`DNSIncoming._log_exception_debug` and the four `QuietLogger` exception-dedup methods stored an unbounded `_seen_logs` dict keyed by `str(sys.exc_info()[1])`. The seven `IncomingDecodeError` messages raised from `_read_name` / `_decode_labels_at_offset` (RFC 6762 §18 name-decoding error paths) all embed `self.source` — the peer's ephemeral source port, varying per packet — plus byte `offset` and pointer `link`, so every attacker-influenced combination produced a fresh dedup key. The stored value was the full `sys.exc_info()` triple, whose traceback's frame locals retained `self.data` (the raw inbound packet, up to 8966 bytes per RFC 6762 §17). Each unique malformed packet therefore pinned ~9 KB until process exit.\n\nAny unauthenticated host on the local link (UDP/5353, `224.0.0.251` / `ff02::fb`) can drive memory growth at line rate; that includes a guest on the same Wi-Fi, a compromised IoT device, or a container on a shared bridge. On memory-constrained deployments (Home Assistant on Raspberry-Pi-class hardware is the canonical victim) sustained traffic trivially OOM-kills the process, and mDNS-dependent features (HomeKit, Chromecast/Matter, AirPlay, printers) degrade or fail.\n\n### Patches\nFixed in `zeroconf` 0.149.6 ([PR #1717](https://github.com/python-zeroconf/python-zeroconf/pull/1717)). Upgrade to `>= 0.149.6`.\n\n### Workarounds\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- [PR #1717](https://github.com/python-zeroconf/python-zeroconf/pull/1717), fix\n- [Issue #1714](https://github.com/python-zeroconf/python-zeroconf/issues/1714), public tracking issue\n- [RFC 6762 §17](https://www.rfc-editor.org/rfc/rfc6762#section-17), [RFC 6762 §18](https://www.rfc-editor.org/rfc/rfc6762#section-18), [CWE-400](https://cwe.mitre.org/data/definitions/400.html)\n\n## Affected packages\n\n- `zeroconf < 0.149.6`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `zeroconf 0.149.6`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}