dbcve.org
FedoraOperating system · Fedoraproject

CVE-2022-2601

HIGH · 8.6 CVSS v3.1 Published 2022-12-14
Fix available
A fix is available. Upgrade to after 2.06 or later.
See remediation →
89/100
Remediation priority · High
No privileges

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 buffer overflow was found in grub_font_construct_glyph(). A malicious crafted pf2 font can lead to an overflow when calculating the max_glyph_size value, allocating a smaller than needed buffer for the glyph, this further leads to a buffer overflow and a heap based out-of-bounds write. An attacker may use this vulnerability to circumvent the secure boot mechanism.

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 · high confidence

A buffer overflow exists in GRUB2's font_construct_glyph() function where a malicious pf2 font file causes incorrect calculation of max_glyph_size, resulting in allocation of an undersized buffer. This leads to a heap-based out-of-bounds write that can be exploited to circumvent secure boot verification.

MitigationUpdate GRUB2 to the patched version that corrects the max_glyph_size calculation. Verify all font files in the boot chain are trusted and consider implementing font file validation before loading.

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
FedoraOperating system
Affected:= 37
Enterprise Linux EusOperating system
Affected:= 9.0
Enterprise Linux For Power Little Endian EusOperating system
Affected:= 9.0
Enterprise Linux Server AusOperating system
Affected:= 8.2
Enterprise Linux Server For Power Little Endian Update Services For Sap SolutionsOperating system
Affected:= 8.1= 8.2= 9.0
Enterprise Linux Server TusOperating system
Affected:= 8.2
Enterprise Linux Server Update Services For Sap SolutionsOperating system
Affected:= 8.1= 8.2= 9.0
Grub2Application
Affected:<= 2.06

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
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/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 GRUB2 version
    Run 'grub2-mkversion' or check the installed grub2 package version using your distribution's package manager (e.g., 'rpm -q grub2' or 'dpkg -l grub2')
    Affected if The installed version is 2.06 or lower, or matches one of the affected Fedora/RHEL versions listed
  2. Locate pf2 font files in boot configuration
    Examine GRUB configuration files (typically /boot/grub2/grub.cfg, /boot/efi/EFI/*/grub.cfg, or /etc/default/grub) for 'font' or 'loadfont' commands that reference .pf2 files
    Affected if Custom pf2 font files are explicitly loaded in the GRUB configuration
  3. Check for custom font directory
    Inspect the /boot/grub2/fonts/ directory (or /boot/efi/EFI/*/fonts/) for any .pf2 font files that are not part of the default OS installation
    Affected if Non-standard or custom pf2 font files exist in the boot font directory
  4. Verify UEFI Secure Boot status
    Check if UEFI Secure Boot is enabled on the system (via 'mokutil --sb-state' or BIOS settings) and review any GRUB2-signed certificate policies
    Affected if Secure Boot is enabled and GRUB2 is used as the bootloader, making this vulnerability exploitable for boot verification bypass

A system is affected if it runs GRUB2 version 2.06 or earlier with Secure Boot enabled and loads custom pf2 font files through GRUB configuration, allowing an attacker to potentially bypass secure boot verification via heap-based buffer overflow.

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 2.06
Interim mitigation

Update GRUB2 to the patched version that corrects the max_glyph_size calculation. Verify all font files in the boot chain are trusted and consider implementing font file validation before loading.

Recommended fix Moderate confidence

GRUB2 version > 2.06 (typically 2.07 or later point release)

  1. 1. Obtain the fixed GRUB2 package from your Linux distribution's official repository (Red Hat, Fedora, or upstream)
  2. 2. Download or access the updated grub2, grub2-common, grub2-pc, or grub2-efi-x64 packages depending on your system architecture
  3. 3. Ensure you have a verified, secure boot chain and a way to recover (e.g., live media, rescue mode) in case of boot failure
  4. 4. Install the updated GRUB2 package using your distribution's package manager (dnf for RHEL/Fedora, yum for older systems)
  5. 5. Rebuild the GRUB configuration if necessary: for BIOS systems run 'grub2-mkconfig -o /boot/grub2/grub.cfg', for UEFI systems run 'grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg' or the appropriate path
  6. 6. Reinstall GRUB2 to the boot disk/partition: for BIOS use 'grub2-install /dev/sdX', for UEFI use 'grub2-install --efi-directory=/boot/efi'
  7. 7. Verify the installed GRUB2 version matches the fixed release (greater than 2.06)
  8. 8. Reboot the system and verify normal boot functionality
Caveat Upgrading GRUB2 carries risk of boot failure; ensure you have recovery media available. Custom GRUB configurations may need adjustment. Secure Boot signatures must be re-enrolled if using custom signed binaries.

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

Fix this in Fedora Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA6.0 h
34.0 hours of engineering $5,940
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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-2022-2601 in production — separate from our analysis above.

No notes yet

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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