CVE-2023-5370

Speculative-execution exposure via premature SMCCC check

Published Oct 4, 2023 · Updated Feb 13, 2025

Improper initialization in the arm64 boot path of FreeBSD 13.2 allows local users to target CPU 0 with speculative-execution side-channel attacks. The boot path queries firmware for an SMCCC workaround before SMCCC support is initialized, so CPU 0 installs no SMCCC-based mitigation. Exposure is limited to AArch64 systems whose CPU 0 lacks CSV2 and PSTATE.SSBS; FreeBSD does not specify what data attackers can recover.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in the arm64 boot path of FreeBSD 13.2 allows local users to target CPU 0 with speculative-execution side-channel attacks. The boot path queries firmware for an SMCCC workaround before SMCCC support is initialized, so CPU 0 installs no SMCCC-based mitigation. Exposure is limited to AArch64 systems whose CPU 0 lacks CSV2 and PSTATE.SSBS; FreeBSD does not specify what data attackers can recover.

The record

CVE
CVE-2023-5370
Published
Oct 4, 2023
Updated
Feb 13, 2025
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-665
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=13.2-RELEASE <p4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=13.2-RELEASE <p4

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-665Improper Initialization

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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