ZephyrOperating system · Zephyrproject

CVE-2023-4260

CRITICAL · 10.0 CVSS v3.1 Published 2023-09-27
Fix available
A fix is available. Upgrade to after 3.4.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges 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
Potential off-by-one buffer overflow vulnerability in the Zephyr fuse file system.

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 potential off-by-one buffer overflow vulnerability exists in the Zephyr RTOS FUSE (Filesystem in Userspace) implementation. This class of flaw occurs when a loop or memory operation exceeds a buffer boundary by one byte, potentially allowing adjacent memory corruption that could be leveraged for code execution or denial of service.

MitigationApply the official Zephyr project patch when available, update to the latest patched Zephyr RTOS version, and verify FUSE functionality post-update.

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
ZephyrOperating system
Affected:<= 3.4.0

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Identify Zephyr RTOS version
    Check the kernel version reported by the Zephyr system, or inspect the build configuration (typically in prj.conf or Kconfig) for the ZEPHYR_VERSION or KERNEL_VERSION macros. Alternatively, check the west manifest or version file in the Zephyr source tree.
    Affected if The installed or compiled Zephyr version is 3.4.0 or lower.
  2. Verify FUSE module is enabled
    Examine the build configuration files (prj.conf, defconfig, or Kconfig) for CONFIG_FUSE or similar FUSE-related configuration options. Look for entries like CONFIG_FUSE_FUSE or CONFIG_FUSE_VFS.
    Affected if FUSE (Filesystem in Userspace) support is enabled in the Zephyr build configuration.
  3. Inspect FUSE implementation code
    Locate the FUSE source files in the Zephyr codebase (typically under subsys/fs/fuse.c or similar paths in the filesystem module). Check the loop boundaries and buffer handling in functions performing read/write operations.
    Affected if The FUSE implementation code contains loops or memory operations that interact with buffers and could exceed boundaries by one byte.
  4. Check for FUSE device configuration
    Review the device tree or board configuration files for FUSE device definitions. Look for any custom FUSE device setups or overlays that might instantiate the FUSE subsystem.
    Affected if A FUSE device or filesystem instance is configured and will be initialized at runtime.

The environment is affected if it runs Zephyr version 3.4.0 or lower with FUSE (Filesystem in Userspace) enabled and configured in the build.

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.

From vendor data
Upgrade available Upgrade to a release after 3.4.0
Interim mitigation

Apply the official Zephyr project patch when available, update to the latest patched Zephyr RTOS version, and verify FUSE functionality post-update.

Fix this in Zephyr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-4260 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2023-4260 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