CVE-2025-0686

Publication date 18 February 2025

Last updated 5 March 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.4 · Medium

Score breakdown

A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub’s romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub’s internal critical data and can result in arbitrary code execution by-passing secure boot protections.

Read the notes from the security team

Status

Package Ubuntu Release Status
grub2 24.10 oracular
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
grub2-signed 24.10 oracular
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-unsigned 24.10 oracular
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

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)

Severity score breakdown

Parameter Value
Base score 6.4 · Medium
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