Your submission was sent successfully! Close

You have successfully unsubscribed! Close

Thank you for signing up for our newsletter!
In these regular emails you will find the latest updates about Ubuntu and upcoming events where you can meet our team.Close

CVE-2020-25632

Published: 2 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.

Notes

AuthorNote
alexmurray
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.

Priority

Medium

Cvss 3 Severity Score

7.5

Score breakdown

Status

Package Release Status
grub2-unsigned
Launchpad, Ubuntu, Debian
hirsute
Released (2.04-1ubuntu42)
impish
Released (2.04-1ubuntu45)
trusty Does not exist

bionic
Released (2.04-1ubuntu44.1.2)
focal
Released (2.04-1ubuntu44.2)
groovy
Released (2.04-1ubuntu44.2)
upstream Needs triage

kinetic Not vulnerable
(2.06-2ubuntu12)
lunar Not vulnerable
(2.06-2ubuntu16)
jammy Not vulnerable
(2.06-2ubuntu7)
mantic Not vulnerable
(2.06-2ubuntu17)
xenial
Released (2.04-1ubuntu42)
grub2-signed
Launchpad, Ubuntu, Debian
impish
Released (1.169)
bionic
Released (1.167~18.04.5)
focal
Released (1.167.2)
groovy
Released (1.167.2)
hirsute
Released (1.164)
trusty Needed

upstream Needs triage

kinetic Not vulnerable
(1.185)
lunar Not vulnerable
(1.192)
jammy Not vulnerable
(1.180)
mantic Not vulnerable
(1.193)
xenial
Released (1.164)
grub2
Launchpad, Ubuntu, Debian
upstream Needs triage

mantic Not vulnerable
(does not affect Secure Boot)
bionic Not vulnerable
(does not affect Secure Boot)
focal Not vulnerable
(does not affect Secure Boot)
jammy Not vulnerable
(does not affect Secure Boot)
kinetic Not vulnerable
(does not affect Secure Boot)
lunar Not vulnerable
(does not affect Secure Boot)
trusty Not vulnerable
(does not affect Secure Boot)
xenial Not vulnerable
(does not affect Secure Boot)

Severity score breakdown

Parameter Value
Base score 7.5
Attack vector Local
Attack complexity High
Privileges required High
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H