CVE-2020-15706

Published: 29 July 2020

GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions.

From the Ubuntu security team

Chris Coulson discovered that the GRUB2 function handling code did not properly handle a function being redefined, leading to a use-after-free vulnerability. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions.

Priority

High

CVSS 3 base score: 6.4

Status

Package Release Status
grub2
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable
(2.04-1ubuntu26.1)
Ubuntu 20.04 LTS (Focal Fossa)
Released (2.04-1ubuntu26.1)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (2.02-2ubuntu8.16)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (2.02~beta2-36ubuntu3.26)
Ubuntu 14.04 ESM (Trusty Tahr)
Released (2.02~beta2-9ubuntu1.20)
grub2-signed
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable
(1.147)
Ubuntu 20.04 LTS (Focal Fossa)
Released (1.142.3)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (1.93.18)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (1.66.26)
Ubuntu 14.04 ESM (Trusty Tahr)
Released (1.34.22)