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Cortex A77 FirmwareOperating system · Arm

CVE-2023-34320

MEDIUM · 5.5 CVSS v3.1 Published 2023-12-08
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
Cortex-A77 cores (r0p0 and r1p0) are affected by erratum 1508412 where software, under certain circumstances, could deadlock a core due to the execution of either a load to device or non-cacheable memory, and either a store exclusive or register read of the Physical Address Register (PAR_EL1) in close proximity.

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

Hardware erratum in ARM Cortex-A77 cores (r0p0, r1p0) where specific instruction sequences combining either a load to device/non-cacheable memory with either a store exclusive or PAR_EL1 register read in close proximity can cause a core deadlock. This is a CPU hardware bug, not a software vulnerability.

MitigationApply firmware/microcode updates from the hardware vendor (ARM or OEM) that address erratum 1508412, or implement OS-level workarounds to avoid the triggering instruction sequences if firmware updates are unavailable.

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
Cortex A77 FirmwareOperating system
Affected:= r0p0= r1p0
XenOperating system
Affected:all versions

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
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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. Identify the CPU model
    Check the processor identification (e.g., via /proc/cpuinfo on Linux, or system firmware/DMIDEcode output) to determine if the system uses an ARM Cortex-A77 core
    Affected if The CPU is not an ARM Cortex-A77, then the system is not affected by this specific erratum
  2. Determine the CPU revision stepping
    Retrieve the revision number of the Cortex-A77 core (typically shown as part of the CPUID or in firmware tables)
    Affected if The revision is r0p0 or r1p0, indicating the affected stepping versions; revisions r2p0 and later are not affected by this erratum
  3. Check for Xen hypervisor presence
    Determine if Xen hypervisor is running on the system (e.g., check for Xen dom0 or xenstored processes, or inspect hypervisor version via xl info or xm info)
    Affected if Xen is installed and running, as all versions of Xen are affected when deployed on vulnerable Cortex-A77 hardware (r0p0, r1p0)
  4. Verify firmware/microcode update status
    Consult system firmware or vendor documentation to confirm whether microcode or firmware updates addressing ARM erratum 1508412 have been applied
    Affected if No firmware update has been applied and the CPU matches the affected model/revision, indicating the hardware bug remains present

A system is affected if it contains an ARM Cortex-A77 CPU at revision r0p0 or r1p0, with no firmware microcode update applied, and especially if running Xen hypervisor on such hardware.

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 firmware/microcode updates from the hardware vendor (ARM or OEM) that address erratum 1508412, or implement OS-level workarounds to avoid the triggering instruction sequences if firmware updates are unavailable.

Recommended fix Moderate confidence

Cortex-A77 r2p0 or later firmware revision, or obtain vendor-specific firmware patch for erratum 1508412

  1. Identify the specific hardware platform running the affected Cortex-A77 r0p0 or r1p0 cores
  2. Contact the hardware vendor (e.g., server manufacturer, board manufacturer) to obtain firmware/microcode updates that address erratum 1508412
  3. Apply the vendor-provided firmware update to the affected systems
  4. After firmware update, verify the system is running on a fixed Cortex-A77 revision (r2p0 or later) or that the erratum is otherwise mitigated
  5. For Xen environments, also ensure Xen is updated to a version that properly handles the erratum if such Xen updates exist
Caveat Firmware updates carry risk and may require system downtime; verify compatibility with your specific hardware platform before applying

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

Fix this in Cortex A77 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2023-34320 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