CVE-2019-6477: Fedoraproject Fedora

High severity, CVSS 7.5. EPSS: 4.1% chance of exploitation in the next 30 days.

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

Affected products

• Fedoraproject Fedora: version 30 only; version 31 only
• ISC BIND: from 9.11.7, up to and including 9.11.12; from 9.14.1, up to and including 9.14.7; from 9.15.0, up to and including 9.15.5; version 9.11.5 only; version 9.11.6 only; version 9.11.12 only; …

Published 2019-11-26. Last modified 2026-06-17.