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Fedora CoreosApplication · Redhat

CVE-2022-3675

MEDIUM · 5.5 CVSS v3.1 Published 2022-11-03
Fix available
A fix is available. Upgrade to 37.20221031.1.0 or later.
See remediation →
57/100
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
Fedora CoreOS supports setting a GRUB bootloader password using a Butane config. When this feature is enabled, GRUB requires a password to access the GRUB command-line, modify kernel command-line arguments, or boot non-default OSTree deployments. Recent Fedora CoreOS releases have a misconfiguration which allows booting non-default OSTree deployments without entering a password. This allows someone with access to the GRUB menu to boot into an older version of Fedora CoreOS, reverting any security fixes that have recently been applied to the machine. A password is still required to modify kernel command-line arguments and to access the GRUB command line.

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

Fedora CoreOS implements GRUB bootloader password protection via Butane config to prevent unauthorized access to boot options. A misconfiguration in recent releases allows booting non-default OSTree deployments without entering the configured password, enabling an attacker with physical or console access to revert to older OS versions and bypass recent security patches.

MitigationReview and correct the Butane configuration for GRUB password settings to ensure password is required for booting any OSTree deployment. Verify the fix by testing that all boot options (default and non-default) require authentication.

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
Fedora CoreosApplication
Affected:>= 36.20220820.3.0, < 37.20221031.1.0

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

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

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. Check Fedora CoreOS version
    Run `rpm-ostree status` or examine `/usr/lib/os-release` to identify the current OSTree deployment version
    Affected if Version is >= 36.20220820.3.0 and < 37.20221031.1.0
  2. Verify GRUB password is configured
    Locate and inspect the Butane configuration file (typically at /etc/butane/config.bu or the ignition file used during provisioning) and check for GRUB password settings under the grub or storage sections
    Affected if GRUB password protection is defined in the Butane config
  3. Test non-default boot authentication
    Reboot the system, access the GRUB menu, select a non-default OSTree deployment, and verify whether a password prompt appears before booting
    Affected if Non-default OSTree deployments boot without requiring password authentication

The system is affected if it runs an affected Fedora CoreOS version with GRUB password configured via Butane, yet allows booting non-default OSTree deployments without entering the password.

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 37.20221031.1.0 or later
Fixed in 37.20221031.1.0
Interim mitigation

Review and correct the Butane configuration for GRUB password settings to ensure password is required for booting any OSTree deployment. Verify the fix by testing that all boot options (default and non-default) require authentication.

Recommended fix High confidence

Fedora CoreOS 37.20221031.1.0 or later

  1. Verify current Fedora CoreOS version using `rpm-ostree status`
  2. Schedule a maintenance window for the system update
  3. Back up any critical data or custom configurations
  4. Update to Fedora CoreOS version 37.20221031.1.0 or later using `rpm-ostree upgrade` or `rpm-ostree rebase`
  5. After upgrade, verify the GRUB password configuration is working correctly by checking /boot/grub2/grub.cfg for proper password enforcement on menu entries
  6. Reboot the system to ensure the new OSTree deployment is active with the fixed GRUB configuration
  7. Confirm the fix by attempting to boot a non-default OSTree deployment (it should now require the configured password)
Caveat Standard Fedora CoreOS upgrade considerations apply - ensure custom Butane configs and system configurations are compatible with the target version

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

Fix this in Fedora Coreos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2022-3675 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
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  • Version or environment caveats, and links to real fixes
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