dbcve.org
FreeBSDOperating system

CVE-2023-5370

MEDIUM · 5.5 CVSS v3.1 Published 2023-10-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
On CPU 0 the check for the SMCCC workaround is called before SMCCC support has been initialized. This resulted in no speculative execution workarounds being installed on CPU 0.

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

In the Linux kernel for ARM64, the check for SMCCC (Secure Monitor Call Calling Convention) speculative execution workarounds is invoked on CPU 0 before SMCCC support has been properly initialized. This initialization ordering bug means the boot CPU does not have speculative execution mitigations installed, while other CPUs (brought up later) would have them. The vulnerability stems from a race condition between early boot code and the secure monitor initialization.

MitigationApply the upstream kernel patch that corrects the initialization order to ensure SMCCC support is fully initialized before the workaround check is performed on CPU 0. Update to a kernel version containing the fix.

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

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 FreeBSD version
    Run 'freebsd-version' or 'uname -a' to display the installed FreeBSD version
    Affected if Version is exactly 13.2 (the affected version)
  2. Check system architecture
    Run 'uname -m' or examine output from 'uname -a' to identify the system architecture
    Affected if Architecture is arm64 or aarch64 (the vulnerability only affects ARM64 systems)
  3. Verify SMCCC is present in boot logs
    Review /var/log/dmesg.boot or run 'dmesg | grep -i smccc' to search for SMCCC-related messages during boot
    Affected if SMCCC is present and initialized (vulnerability only applies when SMCCC support exists in the system)
  4. Confirm CPU 0 boot mitigation status
    Examine early boot dmesg output for CPU 0 to verify whether speculative execution mitigations for SMCCC are reported as applied to the boot CPU
    Affected if Mitigations are missing or not reported for CPU 0 while present for other CPUs (indicating the initialization race condition)

A system is affected if running FreeBSD 13.2 on ARM64 architecture with SMCCC support present, where the boot CPU (CPU 0) lacks speculative execution mitigations that later CPUs receive due to the initialization ordering bug.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the upstream kernel patch that corrects the initialization order to ensure SMCCC support is fully initialized before the workaround check is performed on CPU 0. Update to a kernel version containing the fix.

Recommended fix Moderate confidence

FreeBSD 13.3 or 14.x (latest stable release)

  1. 1. Backup all critical data and configuration files before performing any system upgrade
  2. 2. Review the FreeBSD upgrade documentation at https://www.freebsd.org/releases/ for the recommended upgrade procedure
  3. 3. Update the FreeBSD ports tree: portsnap fetch extract (or git clone the ports repository)
  4. 4. Update the base system sources: git clone https://git.FreeBSD.org/src /usr/src
  5. 5. Run freebsd-update fetch install to obtain the latest security patches and system updates
  6. 6. For a major version jump (e.g., 13.2 to 14.x), follow the procedure in /usr/src/UPDATING for the target release
  7. 7. Rebuild third-party software that depends on kernel internals after the upgrade
  8. 8. Reboot the system into the new kernel
Caveat Third-party kernel modules may need recompilation after major version upgrade; review /usr/src/UPDATING for any compatibility notes

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,860
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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-2023-5370 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