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FreeBSDOperating system

CVE-2024-8178

HIGH · 8.8 CVSS v3.1 Published 2024-09-05
Fix available
A fix is available. Upgrade to 13.3 or later.
See remediation →
90/100
Remediation priority · Urgent
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
The ctl_write_buffer and ctl_read_buffer functions allocated memory to be returned to userspace, without initializing it. Malicious software running in a guest VM that exposes virtio_scsi can exploit the vulnerabilities to achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process. A malicious iSCSI initiator could achieve remote code execution on the iSCSI target host.

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

In FreeBSD's bhyve hypervisor, the ctl_write_buffer and ctl_read_buffer functions (part of virtio_scsi) allocate memory to return to userspace without initializing it, leaking uninitialized memory contents. A malicious guest VM with virtio_scsi access can exploit this for code execution in the bhyve process (runs as root), despite Capsicum sandboxing constraints.

MitigationApply the vendor patch which ensures all allocated buffers are properly initialized before use; restrict untrusted VMs from using virtio_scsi until patched.

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:>= 13.0, < 13.3= 13.3= 13.4= 14.0= 14.1

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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. Check FreeBSD version
    Run 'uname -r' or 'freebsd-version -k' to identify the installed FreeBSD version
    Affected if The version matches >= 13.0, < 13.3; = 13.3; = 13.4; = 14.0; or = 14.1
  2. Verify bhyve is installed
    Run 'which bhyve' or 'bhyve --version' to confirm the hypervisor is present on the system
    Affected if bhyve is installed on an affected FreeBSD version
  3. Check if virtio_scsi is available to guests
    Inspect VM configuration files for virtio-scsi device definitions (such as 'virtio-scsi' or 'virtio_scsi' in bhyve command line arguments or VM config files)
    Affected if Any guest VM configuration includes virtio-scsi device passthrough
  4. Identify running bhyve processes with virtio_scsi
    Run 'ps aux | grep bhyve' and examine if any bhyve processes were launched with virtio-scsi controllers (often visible via 'virtio_scsi' in process arguments or associated vmrun scripts)
    Affected if A bhyve instance is running with active virtio_scsi device access from a guest VM

A system is affected if it runs an affected FreeBSD version (13.0-14.1) with bhyve and any guest VM configured to use virtio-scsi, as the flaw only triggers when the virtio_scsi frontend is enabled.

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 13.3 or later
Fixed in 13.3
Interim mitigation

Apply the vendor patch which ensures all allocated buffers are properly initialized before use; restrict untrusted VMs from using virtio_scsi until patched.

Recommended fix Moderate confidence

FreeBSD 14.1 or later for 14.x systems; FreeBSD 13.5 or later for 13.x systems

  1. 1. Identify the current FreeBSD version using 'uname -a' or 'freebsd-version'
  2. 2. Determine the appropriate stable branch for your system (13.x or 14.x)
  3. 3. For FreeBSD 14.x systems: Upgrade to FreeBSD 14.1 or later which contains the security fix
  4. 4. For FreeBSD 13.x systems: Upgrade to FreeBSD 13.5 or later which contains the security fix
  5. 5. After upgrading, verify the fix by checking the release notes for the new version
  6. 6. Test the bhyve and iSCSI functionality to ensure normal operation after the update
Caveat Upgrade to a new minor version may introduce changes to system behavior; review the release notes for any breaking changes before applying in production environments

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,080.

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-2024-8178 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