Vulnerability in Paulsm Zeroconf
CVE-2026-47180
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.__init__, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb). This issue is fixed in version 0.149.5.
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 (29.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.7% 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 < 0.149.5
Weakness classification (CWE)
References
- github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9pgc-3ccv-5… (Patch, Vendor Advisory)
- github.com/python-zeroconf/python-zeroconf/pull/1719 (Patch, Issue Tracking)
- github.com/python-zeroconf/python-zeroconf/commit/f9e23592137f30fdf7ef710dba065… (Patch)
- github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.5 (Release Notes)
Frequently asked questions
- What is CVE-2026-47180?
- CVE-2026-47180 is a medium-severity vulnerability in Paulsm Zeroconf, classified under Uncontrolled Recursion. CVSS score: 6.5/10. Published 2026-07-17.
- How severe is CVE-2026-47180?
- Medium severity. CVSS v3 base score is 6.5 out of 10.