CVE-2020-25632
Publication date 2 March 2021
Last updated 24 July 2024
Ubuntu priority
Cvss 3 Severity Score
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.
Status
Package | Ubuntu Release | Status |
---|---|---|
grub2 | 24.04 LTS noble |
Not affected
|
22.04 LTS jammy |
Not affected
|
|
20.04 LTS focal |
Not affected
|
|
18.04 LTS bionic |
Not affected
|
|
16.04 LTS xenial |
Not affected
|
|
14.04 LTS trusty |
Not affected
|
|
grub2-signed | 24.04 LTS noble |
Not affected
|
22.04 LTS jammy |
Not affected
|
|
20.04 LTS focal |
Fixed 1.167.2
|
|
18.04 LTS bionic |
Fixed 1.167~18.04.5
|
|
16.04 LTS xenial |
Fixed 1.164
|
|
14.04 LTS trusty |
Vulnerable
|
|
grub2-unsigned | 24.04 LTS noble |
Not affected
|
22.04 LTS jammy |
Not affected
|
|
20.04 LTS focal |
Fixed 2.04-1ubuntu44.2
|
|
18.04 LTS bionic |
Fixed 2.04-1ubuntu44.1.2
|
|
16.04 LTS xenial |
Fixed 2.04-1ubuntu42
|
|
14.04 LTS trusty | Not in release |
Notes
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.
Severity score breakdown
Parameter | Value |
---|---|
Base score | 7.5 · High |
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 |
References
Related Ubuntu Security Notices (USN)
- USN-4992-1
- GRUB 2 vulnerabilities
- 18 June 2021