Resource exhaustion in Paulsm Zeroconf
CVE-2026-47184
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (31.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Paulsm Zeroconf
- Python-Zeroconf — versions < 0.149.7
Weakness classification (CWE)
References
- github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-rfg2-pjw2-5… (Patch, Vendor Advisory)
- github.com/python-zeroconf/python-zeroconf/issues/1715 (Patch, Issue Tracking)
- github.com/python-zeroconf/python-zeroconf/pull/1718 (Patch, Issue Tracking)
- github.com/python-zeroconf/python-zeroconf/commit/0ad3f37b5b852b8f614d322283d14… (Patch)
- github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.7 (Release Notes)
Frequently asked questions
- What is CVE-2026-47184?
- CVE-2026-47184 is a medium-severity vulnerability in Paulsm Zeroconf, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-07-17.
- How severe is CVE-2026-47184?
- Medium severity. CVSS v3 base score is 6.5 out of 10.