CVE-2021-3418
Published: 2 March 2021
If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.
Notes
| Author | Note |
|---|---|
| sbeattie | does not affect grub2 as packaged in Ubuntu, we already had to address CVE-2020-15705. |
| sbeattie | grub2-unsigned will contain fixes and supersede grub2, which will contain only BIOS grub bits. |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
grub2 Launchpad, Ubuntu, Debian |
jammy |
Not vulnerable
|
| trusty |
Not vulnerable
|
|
| xenial |
Not vulnerable
|
|
| impish |
Not vulnerable
|
|
| bionic |
Not vulnerable
|
|
| focal |
Not vulnerable
|
|
| groovy |
Not vulnerable
|
|
| hirsute |
Not vulnerable
|
|
| upstream |
Not vulnerable
|
|
|
grub2-signed Launchpad, Ubuntu, Debian |
bionic |
Not vulnerable
|
| focal |
Not vulnerable
|
|
| groovy |
Not vulnerable
|
|
| hirsute |
Not vulnerable
|
|
| jammy |
Not vulnerable
|
|
| trusty |
Not vulnerable
|
|
| upstream |
Needs triage
|
|
| xenial |
Not vulnerable
|
|
| impish |
Not vulnerable
|
|
|
grub2-unsigned Launchpad, Ubuntu, Debian |
bionic |
Not vulnerable
|
| focal |
Not vulnerable
|
|
| groovy |
Not vulnerable
|
|
| hirsute |
Not vulnerable
|
|
| jammy |
Not vulnerable
|
|
| trusty |
Not vulnerable
|
|
| upstream |
Needs triage
|
|
| xenial |
Not vulnerable
|
|
| impish |
Not vulnerable
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.4 |
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | High |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H |