dnspython is a DNS toolkit for Python. Prior to 2.9.0, dns.name.fromwireparser follows attacker-controlled DNS compression pointer chains without a hop limit. A malicious DNS wire-format message can force excessive pointer traversal during name decompression, causing high CPU use, application degradation, or denial of service in applications that process untrusted DNS messages. This issue is fixed in version 2.9.0.

Impact A maliciously crafted DNS message may cause dns.name.fromwireparser() to use excessive CPU for DNS name decompression. Applications that process untrusted DNS wire form messages with dnspython may be degraded or DoS'd by the extra CPU use required.

Patches This problem is fixed in dnspython 2.9.0.

Workarounds There are no known workarounds.

Credit Evgenios Gkritsis, Department of Informatics, University of Piraeus & Athena Research Center, Greece Constantinos Patsakis, Department of Informatics, University of Piraeus & Athena Research Center, Greece George Stergiopoulos, Department of Informatics, Athens University of Economics and Business, Greece