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
| Author | Note |
|---|---|
| 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
Status
| Package | Release | Status |
|---|---|---|
|
grub2-unsigned Launchpad, Ubuntu, Debian |
hirsute |
Released
(2.04-1ubuntu42)
|
| xenial |
Pending
(2.04-1ubuntu42)
|
|
| impish |
Released
(2.04-1ubuntu45)
|
|
| upstream |
Needs triage
|
|
| trusty |
Does not exist
|
|
| bionic |
Released
(2.04-1ubuntu44.1.2)
|
|
| focal |
Released
(2.04-1ubuntu44.2)
|
|
| groovy |
Released
(2.04-1ubuntu44.2)
|
|
| kinetic |
Not vulnerable
(2.06-2ubuntu12)
|
|
| lunar |
Not vulnerable
(2.06-2ubuntu16)
|
|
| jammy |
Not vulnerable
(2.06-2ubuntu7)
|
|
|
grub2-signed Launchpad, Ubuntu, Debian |
impish |
Released
(1.169)
|
| upstream |
Needs triage
|
|
| trusty |
Needed
|
|
| bionic |
Released
(1.167~18.04.5)
|
|
| hirsute |
Released
(1.164)
|
|
| focal |
Released
(1.167.2)
|
|
| groovy |
Released
(1.167.2)
|
|
| kinetic |
Not vulnerable
(1.185)
|
|
| lunar |
Not vulnerable
(1.192)
|
|
| xenial |
Pending
(1.164)
|
|
| jammy |
Not vulnerable
(1.180)
|
|
|
grub2 Launchpad, Ubuntu, Debian |
trusty |
Needed
|
| xenial |
Needed
|
|
| bionic |
Needed
|
|
| focal |
Needed
|
|
| jammy |
Not vulnerable
(2.06-2ubuntu7)
|
|
| kinetic |
Not vulnerable
(2.06-2ubuntu12)
|
|
| lunar |
Not vulnerable
(2.06-2ubuntu16)
|
|
| upstream |
Needs triage
|
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 |