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Grub2Application · Gnu

CVE-2025-0684

MEDIUM · 6.4 CVSS v3.1 Published 2025-03-03
Fix available
A fix is available. Upgrade to after 2.12 or later.
See remediation →
66/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in grub2. When performing a symlink lookup from a reiserfs filesystem, grub's reiserfs fs module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly 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_reiserfs_read_symlink() will call grub_reiserfs_read_real() with a overflown length parameter, leading to a heap based out-of-bounds write during data reading. This flaw may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution, by-passing secure boot protections.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Integer overflow in grub2's reiserfs module allows a maliciously crafted filesystem to cause buffer size calculations to underflow, leading to heap-based out-of-bounds write during symlink reading. This can corrupt critical data and enable arbitrary code execution, bypassing Secure Boot protections.

MitigationUpdate grub2 to patched version, re-sign bootloader for Secure Boot if applicable, and consider disabling reiserfs support in grub if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Grub2Application
Affected:<= 2.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed grub2 version
    Run 'grub2-install --version' or check your distribution's package manager for the grub2 version installed (e.g., 'rpm -q grub2' or 'dpkg -l grub2')
    Affected if The installed version is 2.12 or lower (the vulnerability exists in grub2 <= 2.12)
  2. Locate the reiserfs grub module
    Search for the reiserfs module file in grub's module directory - common paths include /usr/lib/grub/*/reiserfs.mod or /boot/grub/*/reiserfs.mod
    Affected if The reiserfs module file exists on the system (vulnerability requires this module to be present)
  3. Check if reiserfs module is loaded in grub config
    Inspect your grub.cfg or grub configuration for 'insmod reiserfs' or 'load_module reiserfs' statements indicating the module is enabled
    Affected if The reiserfs module is loaded or could be loaded at boot time (the vulnerable code path is only reachable when the module is active)
  4. Determine if reiserfs filesystem usage is possible
    Review /etc/fstab and mounted filesystems to check if any reiserfs volumes exist or could be connected; check bootloader configuration for any reiserfs-related menu entries
    Affected if Reiserfs filesystems are present or could be presented to grub at boot (exploitation requires mounting a malicious reiserfs volume)

You are affected if grub2 version is 2.12 or lower AND the reiserfs module is available/loadable on your system and could be triggered by mounting a reiserfs filesystem.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 2.12
Interim mitigation

Update grub2 to patched version, re-sign bootloader for Secure Boot if applicable, and consider disabling reiserfs support in grub if not required.

Recommended fix High confidence

Grub2 version greater than 2.12 (check vendor security advisory for exact fixed version)

  1. Check your current grub2 version using: rpm -qa | grep grub2 or dpkg -l | grep grub2
  2. Verify the reiserfs-progs package is also updated: rpm -qa | grep reiserfs
  3. For RHEL/CentOS systems, update via: yum update grub2* or dnf update grub2*
  4. After update, regenerate grub configuration: grub2-mkconfig -o /boot/grub2/grub.cfg (or /boot/efi/EFI/*/grub.cfg for UEFI systems)
  5. Reboot the system to load the updated grub bootloader
  6. Verify the new grub version is loaded: grub2-install --version
Caveat Ensure bootable rescue media is available in case of boot issues after upgrade; test grub configuration before reboot

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Grub2 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-0684 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data