dbcve.org
FreeBSDOperating system

CVE-2022-23084

HIGH · 7.5 CVSS v3.1 Published 2024-02-15
Fix available
A fix is available. Upgrade to 12.3 or later.
See remediation →
77/100
Remediation priority · High
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 total size of the user-provided nmreq to nmreq_copyin() was first computed and then trusted during the copyin. This time-of-check to time-of-use bug could lead to kernel memory corruption. On systems configured to include netmap in their devfs_ruleset, a privileged process running in a jail can affect the host environment.

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 time-of-check to time-of-use (TOCTOU) vulnerability in the netmap subsystem's nmreq_copyin() function allows a privileged process within a FreeBSD jail to corrupt kernel memory and escape isolation to the host system. The bug stems from trusting the user-provided nmreq size calculation before performing the copy operation.

MitigationRemove netmap from the devfs_ruleset configuration in affected FreeBSD systems until an official patch is applied; or apply vendor-supplied patches to the netmap code in the FreeBSD kernel.

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:>= 12.0, < 12.3= 12.3= 13.0

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

CVSS:3.1/AV:L/AC:H/PR:H/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 'freebsd-version -k' or 'uname -r' to obtain the running kernel version
    Affected if The version is 12.0, 12.1, 12.2, 12.3, or 13.0 (any version in the affected range >=12.0 through 13.0)
  2. Verify netmap kernel module is loaded
    Run 'kldstat | grep netmap' or check for /dev/netmap device entry
    Affected if The netmap kernel module is loaded or the netmap device node exists in /dev
  3. Inspect devfs_ruleset for netmap access
    Examine the devfs_ruleset configuration file (typically /etc/devfs.rules or system configuration) and check for 'netmap' device rules applied to the jail
    Affected if The jail's devfs_ruleset includes rules that expose the netmap device to the jail environment
  4. Confirm process is running inside a FreeBSD jail
    Run 'jls' or check if process is within a jail context using 'jexec' capabilities
    Affected if The target process executes within a FreeBSD jail with netmap device access

A system is affected if it runs an affected FreeBSD version (12.0-13.0), has netmap exposed to a jail via devfs_ruleset, and a privileged process within that jail can access the netmap subsystem.

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 12.3 or later
Fixed in 12.3
Interim mitigation

Remove netmap from the devfs_ruleset configuration in affected FreeBSD systems until an official patch is applied; or apply vendor-supplied patches to the netmap code in the FreeBSD kernel.

Recommended fix High confidence

FreeBSD 12.4 or later for 12.x systems; FreeBSD 13.1 or later for 13.0 systems

  1. 1. Identify the current FreeBSD version using: uname -a
  2. 2. For systems running FreeBSD 12.x (12.0 through 12.3): Upgrade to FreeBSD 12.4 or later stable release
  3. 3. For systems running FreeBSD 13.0: Upgrade to FreeBSD 13.1 or later stable release
  4. 4. To upgrade, run: freebsd-update fetch && freebsd-update install OR use pkg for binary upgrades if using RELEASE
  5. 5. Reboot the system after applying the update
  6. 6. Verify the new version is running: uname -a
Caveat Standard FreeBSD upgrade; review /usr/src/UPDATING for any compatibility notes before upgrading

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation3.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
24.0 hours of engineering $4,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,720.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2022-23084 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