CVE-2020-8617: Canonical Ubuntu Linux

Medium severity, CVSS 5.9. EPSS: 93.4% chance of exploitation in the next 30 days.

Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 14.04 only; version 16.04 only; version 18.04 only; version 19.10 only; version 20.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 31 only; version 32 only
• ISC BIND: from 9.0.0, up to and including 9.11.18; from 9.12.0, up to and including 9.12.4; from 9.13.0, up to and including 9.13.7; from 9.14.0, up to and including 9.14.11; from 9.15.0, up to and including 9.15.6; from 9.16.0, up to and including 9.16.2; …
• Opensuse Leap: version 15.1 only; version 15.2 only

Published 2020-05-19. Last modified 2026-06-17.