Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_M
CVE-2026-47184Zeroconf: Unbounded DNS record cache allows LAN-local memory exhaustion via multicast flood
Medium 6.5
In plain English
A medium-severity resource allocation without limits in python-zeroconf from python-zeroconf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.7, DNSCache._async_add inserted every response record into cache, _expirations, _expire_heap, and service_cache without a cap, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to multicast valid mDNS responses with unique names and cause memory exhaustion, slower cache lookups, slower async_expire passes, and broken discovery, registration, and ServiceBrowser callbacks. This issue is fixed in version 0.149.7.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-zeroconf | no fix listed | DEBIAN-CVE-2026-47184 |
| Debian:13 | python-zeroconf | no fix listed | DEBIAN-CVE-2026-47184 |
| Debian:14 | python-zeroconf | 0.149.7-1 | DEBIAN-CVE-2026-47184 |
| PyPI | zeroconf | 0.149.7 | GHSA-rfg2-pjw2-56x2 |
| PyPI | zeroconf | 0.149.7 | PYSEC-2026-3439 |
| Ubuntu:22.04:LTS | python-zeroconf | no fix listed | UBUNTU-CVE-2026-47184 |
| Ubuntu:24.04:LTS | python-zeroconf | no fix listed | UBUNTU-CVE-2026-47184 |
| Ubuntu:26.04:LTS | python-zeroconf | no fix listed | UBUNTU-CVE-2026-47184 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| python-zeroconf | python-zeroconf | < 0.149.7 |
Weakness: CWE-770 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-rfg2-pjw2-56x2 x_refsource_CONFIRM
- https://github.com/python-zeroconf/python-zeroconf/issues/1715 x_refsource_MISC
- https://github.com/python-zeroconf/python-zeroconf/pull/1718 x_refsource_MISC
- https://github.com/python-zeroconf/python-zeroconf/commit/0ad3f37b5b852b8f614d322283d148efb2cef6e4 x_refsource_MISC
- https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.7 x_refsource_MISC