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FreeBSDOperating system

CVE-2024-25940

MEDIUM · 6.3 CVSS v3.1 Published 2024-02-15
Fix available
A fix is available. Upgrade to 13.2 / 14.0 or later.
See remediation →
69/100
Remediation priority · Elevated
Remotely reachable 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
`bhyveload -h <host-path>` may be used to grant loader access to the <host-path> directory tree on the host. Affected versions of bhyveload(8) do not make any attempt to restrict loader's access to <host-path>, allowing the loader to read any file the host user has access to. In the bhyveload(8) model, the host supplies a userboot.so to boot with, but the loader scripts generally come from the guest image. A maliciously crafted script could be used to exfiltrate sensitive data from the host accessible to the user running bhyhveload(8), which is often the system root.

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

bhyveload's `-h` option allows mounting a host directory into the guest VM, but the loader does not restrict access to just that directory. A malicious guest OS image containing a crafted loader script can read any file accessible to the host user (often root) outside the intended host-path, enabling data exfiltration.

MitigationUntil a patch is available, avoid using `-h` with untrusted guest images, or run bhyveload with a dedicated non-root user account and restrict file permissions carefully.

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
FreeBSDOperating system
Affected:< 13.2>= 13.3, < 14.0= 13.2= 14.0

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
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

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. Verify FreeBSD version
    Run `uname -r` or check `/etc/os-release` to identify the installed FreeBSD version
    Affected if The version is < 13.2, = 13.2, >= 13.3 and < 14.0, or = 14.0
  2. Confirm bhyveload installation
    Check for the presence of bhyveload binary: `which bhyveload` or `ls -la /usr/sbin/bhyveload`
    Affected if bhyveload is installed on the system
  3. Identify bhyveload usage with -h option
    Search for scripts, cron jobs, or configuration files containing 'bhyveload' and '-h': `grep -r "bhyveload.*-h" /etc /var /home 2>/dev/null` and review command history for bhyveload commands
    Affected if The -h option is used to mount a host directory into guest VMs
  4. Check running VM processes
    Look for active bhyveload processes: `ps aux | grep bhyveload`
    Affected if bhyveload is currently running with -h option mounting a host directory
  5. Review VM configurations
    Examine any VM configuration files or startup scripts in directories like `/usr/local/etc/bhyve/`, `/etc/bhyve/`, or custom VM scripts
    Affected if VM configurations reference the -h flag for directory sharing

A system is affected if it runs a vulnerable FreeBSD version (13.2, 14.0, or between 13.3-14.0) AND uses bhyveload with the -h option to mount host directories into untrusted guest VMs.

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 13.2 / 14.0 or later
Fixed in 13.214.0
Interim mitigation

Until a patch is available, avoid using `-h` with untrusted guest images, or run bhyveload with a dedicated non-root user account and restrict file permissions carefully.

Recommended fix Moderate confidence

FreeBSD 14.1 or later stable release

  1. Identify the current FreeBSD version using `uname -r` or `freebsd-version -u`
  2. Upgrade to FreeBSD 14.1 or later, which contains the fix for this vulnerability
  3. After upgrade, verify the bhyveload version includes the fix by checking the release notes or consulting security.freebsd.org/advisories/
  4. If immediate upgrade is not possible, avoid using `bhyveload -h` with untrusted guest images
  5. Ensure bhyveload runs with minimal privileges if possible, not as root
Caveat Standard FreeBSD upgrade considerations apply - review /usr/src/UPDATING for any manual intervention steps, and ensure all third-party software is compatible with the new version

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation4.0 h
  • Implementation24.0 h
  • Testing12.0 h
  • Review / QA6.0 h
46.0 hours of engineering $8,000
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,800.

Scan for this in your stack

Free · runs locally
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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-2024-25940 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