CVE-2025-61663
Publication date 18 November 2025
Last updated 19 November 2025
Ubuntu priority
Description
A vulnerability has been identified in the GRUB2 bootloader's normal command that poses an immediate Denial of Service (DoS) risk. This flaw is a Use-after-Free issue, caused because the normal command is not properly unregistered when the module is unloaded. An attacker who can execute this command can force the system to access memory locations that are no longer valid. Successful exploitation leads directly to system instability, which can result in a complete crash and halt system availability. Impact on the data integrity and confidentiality is also not discarded.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| grub2 | 25.10 questing |
Not affected
|
| 25.04 plucky |
Not affected
|
|
| 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 | Ignored update incompatible with kernel | |
| grub2-unsigned | 25.10 questing |
Needs evaluation
|
| 25.04 plucky |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| grub2-signed | 25.10 questing |
Needs evaluation
|
| 25.04 plucky |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty | Ignored update incompatible with kernel |
Notes
eslerm
the grub2 package does not affect Ubuntu's Secure Boot grub2-unsigned contains Secure Boot security fixes grub2 and grub2-unsigned should have same major version Ubuntu Secure Boot and ESM do not cover i386 trusty's GA kernel cannot handle new versions of grub Note that key revocation is required to protect against evil housekeeper attacks (such as BlackLotus)
Patch details
| Package | Patch details |
|---|---|
| grub2 |
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
4.9 · Medium
|
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity impact | Low |
| Availability impact | Low |
| Vector | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L |