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Enterprise LinuxOperating system · Redhat

CVE-2022-34303

MEDIUM · 6.7 CVSS v3.1 Published 2022-08-26
Fix available
A fix is available. Upgrade to 2022-06-01 or later.
See remediation →
69/100
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 Eurosoft bootloaders before 2022-06-01. An attacker may use this bootloader to bypass or tamper with Secure Boot protections. In order to load and execute arbitrary code in the pre-boot stage, an attacker simply needs to replace the existing signed bootloader currently in use with this bootloader. Access to the EFI System Partition is required for booting using external media.

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

A vulnerability in Eurosoft bootloaders before June 2022 allows attackers to bypass Secure Boot protections by replacing the existing signed bootloader with a malicious Eurosoft bootloader. The attack requires access to the EFI System Partition, typically achieved through external media booting.

MitigationUpdate Eurosoft bootloaders to versions released after 2022-06-01 and verify that Secure Boot configurations are properly enforced to prevent unauthorized bootloader replacement.

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
Enterprise LinuxOperating system
Affected:= 7.0= 8.0= 9.0
Uefi BootloaderOperating system
Affected:< 2022-06-01
Windows 10Operating system
Affected:all versions= 20h2= 21h1= 21h2= 1607= 1809
Windows 11Operating system
Affected:all versions
Windows 8.1Operating system
Affected:all versions
Windows Rt 8.1Operating system
Affected:all versions
Windows Server 2012Operating system
Affected:all versions= r2
Windows Server 2016Operating system
Affected:all versions= 20h2

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/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. Locate Eurosoft bootloader files in EFI System Partition
    Access the EFI System Partition (ESP) and search for Eurosoft-related bootloader files. On Windows, the ESP is typically mounted as drive letter (e.g., S:) and contains an 'EFI' folder. Use 'dir /s S:\EFI\*euro*' or 'dir /s S:\EFI\*Euro*' to find Eurosoft bootloader files. On Linux, the ESP is typically mounted at /boot/efi/EFI/ and you can use 'find /boot/efi -iname "*euro*"'
    Affected if Eurosoft bootloader files exist in the EFI System Partition and their version/date is before 2022-06-01, or the version cannot be verified
  2. Determine Eurosoft bootloader version or date
    Examine the properties or metadata of the Eurosoft bootloader files found in the EFI System Partition. Check file creation/modification dates. Look for version strings within the bootloader files using 'strings' on Linux or a hex editor on Windows. If a version number is displayed, verify it is at least the 2022-06-01 release or later
    Affected if The Eurosoft bootloader version is earlier than the June 2022 release, or the version cannot be determined and the file dates are before June 2022
  3. Verify Secure Boot status
    On Windows, run 'Confirm-SecureBootUEFI' in PowerShell (requires admin). On Linux, check with 'mokutil --sb-status' or 'sbverify --list /boot/efi/EFI/*/shimx64.efi'. Also check BIOS/UEFI firmware settings for Secure Boot configuration
    Affected if Secure Boot is disabled, or the system has been configured to allow unsigned bootloaders, which would indicate the protection mechanism is not active against this attack
  4. Check for unauthorized or duplicate bootloader entries
    Review bootloader configuration files and boot entries. On Windows, use 'bcdedit /enum all' to list all boot entries. On Linux, check /boot/efi/EFI/*/grub.cfg and /boot/loader/entries/ for unexpected entries. Look for multiple Eurosoft bootloader entries or entries pointing to unexpected file paths
    Affected if Multiple Eurosoft bootloader entries exist, or bootloader entries reference files outside the standard signed bootloader locations, suggesting possible replacement

A system is likely affected if Eurosoft bootloader files are present in the EFI System Partition with a version or file date predating June 2022, or if the bootloader version cannot be verified while Secure Boot status is unclear or disabled.

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.

From vendor data
Upgrade available Upgrade to 2022-06-01 or later
Fixed in 2022-06-01
Interim mitigation

Update Eurosoft bootloaders to versions released after 2022-06-01 and verify that Secure Boot configurations are properly enforced to prevent unauthorized bootloader replacement.

Fix this in Enterprise Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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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-2022-34303 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
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