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.
EPSS: 0.004 (31.9th percentile) — read the EPSS interpretation.
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.
Affected products
- Paulsm Zeroconf
- Python-zeroconf — versions < 0.149.7
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, 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.