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U BootApplication · Denx

CVE-2022-33103

HIGH · 7.8 CVSS v3.1 Published 2022-07-01
Fix available
A fix is available. Upgrade to 2022.07 or later.
See remediation →
80/100
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
Das U-Boot from v2020.10 to v2022.07-rc3 was discovered to contain an out-of-bounds write via the function sqfs_readdir().

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

Das U-Boot bootloader versions v2020.10 through v2022.07-rc3 contains an out-of-bounds write vulnerability in the sqfs_readdir() function, which handles reading SquashFS directory entries. This memory corruption flaw could allow an attacker with local or physical access to corrupt memory and potentially execute arbitrary code by mounting a specially crafted SquashFS filesystem.

MitigationUpgrade Das U-Boot to version v2022.07 or later, which contains the fix for the out-of-bounds write in sqfs_readdir(). If upgrading is not feasible, disable SquashFS support in the U-Boot build configuration.

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
U BootApplication
Affected:>= 2020.10, < 2022.07= 2022.07

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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 U-Boot version
    At boot time, U-Boot displays its version on the console. Alternatively, run the U-Boot `version` command, or inspect the bootloader binary with `strings` and search for version strings like 'U-Boot 202' or check build artifacts/config files.
    Affected if The version is v2020.10 through v2022.07-rc3, or exactly v2022.07. Versions prior to v2020.10 are not affected.
  2. Verify SquashFS support is enabled in U-Boot build
    Examine the U-Boot configuration file (.config) or build settings for CONFIG_SQUASHFS=y or CONFIG_SQUASHFS=m. This is typically found in the U-Boot source directory or build output.
    Affected if CONFIG_SQUASHFS is set to y or m (module). If it is not defined or commented out, the vulnerability cannot be triggered.
  3. Determine if SquashFS filesystems are in use
    Review boot arguments (bootargs), device tree configurations, or partition layouts to check if any SquashFS-based filesystems are mounted or accessed during the boot process.
    Affected if The system boots from or mounts a SquashFS filesystem. If only other filesystem types (ext4, FAT, etc.) are used, exploitation is not possible.
  4. Check for physical/local access exposure
    Assess whether an attacker could provide a specially crafted SquashFS image to the target system, such as via removable media, network boot, or firmware updates.
    Affected if The system allows loading SquashFS images from sources the attacker can influence or control.

A system is affected only if it runs a vulnerable U-Boot version (v2020.10 through v2022.07-rc3 or v2022.07), has SquashFS support compiled in, and actually uses SquashFS filesystems that could be replaced with a malicious image.

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 2022.07 or later
Fixed in 2022.07
Interim mitigation

Upgrade Das U-Boot to version v2022.07 or later, which contains the fix for the out-of-bounds write in sqfs_readdir(). If upgrading is not feasible, disable SquashFS support in the U-Boot build configuration.

Recommended fix Moderate confidence

U-Boot 2022.10 or later

  1. 1. Identify all U-Boot installations in your environment that are version 2020.10 through 2022.07 inclusive
  2. 2. Download U-Boot version 2022.10 or later from the official U-Boot repository (https://source.denx.de/u-boot/u-boot/-/releases)
  3. 3. Build the new U-Boot version for your specific hardware platform using the standard build process (make CROSS_COMPILE=<toolchain> <board>_defconfig && make CROSS_COMPILE=<toolchain>)
  4. 4. Replace the vulnerable U-Boot binary on affected devices or in firmware images
  5. 5. Verify the new U-Boot version is running correctly on affected hardware
Caveat Upgrading U-Boot may introduce subtle hardware-specific incompatibilities; thoroughly test the new version on your target hardware before production deployment

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

Fix this in U Boot Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,790
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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-2022-33103 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