CVE-2025-0677

Publication date 18 February 2025

Last updated 26 February 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, the grub’s UFS module checks the inode’s data size to allocate the internal buffer to read the file content, however, it fails to check if the symlink data size has overflown. When this occurs, grub_malloc() may be called with a smaller value than needed. When further reading the data from the disk into the buffer, the grub_ufs_lookup_symlink() function will write past the end of the allocated size. An attack can leverage this by crafting a malicious filesystem, and as a result, it will corrupt data stored in the heap, allowing for arbitrary code execution used to by-pass secure boot mechanisms.

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