Description
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.
Severity (CVSS)
| Base score | 6.5 |
|---|---|
| Severity | Medium |
| Version | CVSS 3.1 |
| Vector | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Provided by | CNA |
Weaknesses
- CWE-674 — CWE-674: Uncontrolled Recursion
Affected products
| Vendor | Product | Versions |
|---|---|---|
| python-zeroconf | python-zeroconf | < 0.149.5 |
References
- https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-9pgc-3ccv-5297 (x_refsource_CONFIRM)
- https://github.com/python-zeroconf/python-zeroconf/pull/1719 (x_refsource_MISC)
- https://github.com/python-zeroconf/python-zeroconf/commit/f9e23592137f30fdf7ef710dba065da31c79b1cf (x_refsource_MISC)
- https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.5 (x_refsource_MISC)
Generated from the official CVE List on 18 Jul 2026 07:00 UTC.