Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.16, _read_character_string and _read_string in src/zeroconf/_protocol/incoming.py advanced self.offset by attacker-declared RDLENGTH without checking it against self._data_len, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to send a TXT, HINFO, or A/AAAA record with rdlength=65535 and seed DNSCache and ServiceInfo.properties with truncated, attacker-shaped key/value or address records. This issue is fixed in version 0.149.16.
Weakness
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Python-zeroconf | Ubuntu | upstream | * |
Potential Mitigations
Related Attack Patterns
References
- https://github.com/python-zeroconf/python-zeroconf/commit/544449596e645fcaad3834fa0cb614a54f847a82
- https://github.com/python-zeroconf/python-zeroconf/issues/1752
- https://github.com/python-zeroconf/python-zeroconf/pull/1756
- https://github.com/python-zeroconf/python-zeroconf/releases/tag/0.149.16
- https://github.com/python-zeroconf/python-zeroconf/security/advisories/GHSA-qc2x-6f54-m6h9