CVE-2020-25632

Published: 02 March 2021

A flaw was found in grub2 in versions prior to 2.06. The rmmod implementation allows the unloading of a module used as a dependency without checking if any other dependent module is still loaded leading to a use-after-free scenario. This could allow arbitrary code to be executed or a bypass of Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

From the Ubuntu security team

Chris Coulson discovered that the rmmod command in GRUB 2 contained a use-after-free vulnerability. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions.

Priority

Medium

CVSS 3 base score: 7.5

Status

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

Ubuntu 21.04 (Hirsute Hippo)
Released (1.164)
Ubuntu 20.10 (Groovy Gorilla)
Released (1.167.2)
Ubuntu 20.04 LTS (Focal Fossa)
Released (1.167.2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (1.167~18.04.5)
Ubuntu 16.04 ESM (Xenial Xerus) Pending
(1.164)
Ubuntu 14.04 ESM (Trusty Tahr) Needs triage

grub2-unsigned
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo)
Released (2.04-1ubuntu42)
Ubuntu 20.10 (Groovy Gorilla)
Released (2.04-1ubuntu44.2)
Ubuntu 20.04 LTS (Focal Fossa)
Released (2.04-1ubuntu44.2)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (2.04-1ubuntu44.1.2)
Ubuntu 16.04 ESM (Xenial Xerus) Pending
(2.04-1ubuntu42)
Ubuntu 14.04 ESM (Trusty Tahr) Needs triage

Notes

AuthorNote
amurray
CVE title: "grub2: use-after-free in rmmod command"
sbeattie
grub2-unsigned will contain fixes and supersede grub2, which will contain only BIOS grub bits.

References