As per upstream:
A race condition which may occur when discarding malformed packets can result in BIND exiting due to a REQUIRE assertion failure in dispatch.c. An attacker who can cause a resolver to perform queries which will be answered by a server which responds with deliberately malformed answers can cause named to exit, denying service to clients.
Created attachment 1582061 [details]
bind patch for 9.11.8
Created attachment 1582062 [details]
This bind flaw can be exploited by a remote attacker (AV:N). However the attack works only if the attacker could cause the bind server to perform queries on another DNS server and the other DNS server deliberately responds with malformed answers (AC:H). No other special privileges are required by the attacker (PR:L). No user interaction is required from the server side (UI:N). The attacker can cause denial of service (A:H) by causing the named process to exit with an assertion flaw. There is no affect on the Confidentiality or Integrity of the system (C:N/I:N).
Created bind tracking bugs for this issue:
Affects: fedora-all [bug 1722335]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2019:1714 https://access.redhat.com/errata/RHSA-2019:1714
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):
Release notes mentioning CVE-2019-6471 fix:
Stable release branches:
Experimental development branch