dbcve.org
TizenOperating system · Linux

CVE-2021-25437

CRITICAL · 9.8 CVSS v3.1 Published 2021-07-08
Fix available
A fix is available. Upgrade to 5.5 or later.
See remediation →
100/100
Remediation priority · Urgent
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
Improper access control vulnerability in Tizen FOTA service prior to Firmware update JUL-2021 Release allows attackers to arbitrary code execution by replacing FOTA update file.

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

Improper access control in Tizen FOTA (Firmware Over-The-Air) service allows attackers to replace firmware update files before they are applied. Due to missing validation of update file integrity and authenticity, attackers can inject malicious firmware, achieving arbitrary code execution with firmware update privileges.

MitigationApply the JUL-2021 or later firmware update to the Tizen device to obtain proper access control checks and file integrity validation for FOTA updates.

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
TizenOperating system
Affected:< 5.5

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Confirm Tizen OS installation
    Identify the operating system by checking system information files (such as /etc/os-release or similar) for Tizen branding or version markers
    Affected if The system is not running Tizen Linux - this CVE only affects Tizen-based devices
  2. Check Tizen version
    Retrieve the installed Tizen version from system configuration or version files, then compare against the affected range of versions prior to 5.5
    Affected if The installed Tizen version is 5.0 through 5.4 (any version below 5.5) - versions prior to 5.5 lack the proper integrity validation fix
  3. Verify FOTA service presence
    Inspect running services or installed packages to determine if the Firmware Over-The-Air (FOTA) update service is installed and configured on the device
    Affected if The FOTA service is not present or not configured - the vulnerability only applies to systems with FOTA enabled
  4. Check FOTA configuration for integrity validation
    Examine FOTA service configuration files or settings to determine whether file integrity and authenticity validation mechanisms are properly configured for firmware updates
    Affected if FOTA is enabled but integrity validation for update files is missing or disabled - this indicates the vulnerable configuration described in the CVE

The system is affected if it runs Tizen Linux version 5.0-5.4 with the FOTA update service enabled and lacking proper file integrity validation for firmware updates.

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 5.5 or later
Fixed in 5.5
Interim mitigation

Apply the JUL-2021 or later firmware update to the Tizen device to obtain proper access control checks and file integrity validation for FOTA updates.

Recommended fix High confidence

Tizen 5.5 or later with JUL-2021 firmware update

  1. Identify the current Tizen firmware version on the device
  2. Apply the JUL-2021 Firmware update or later (which includes Tizen 5.5 or higher)
  3. Verify the firmware update was successfully applied
  4. Confirm the FOTA service has been updated to the patched version
Caveat Firmware updates carry inherent risks; ensure backups are in place and follow Samsung's official update procedures

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

Fix this in Tizen Scoped from the published advisory
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,840
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,144.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-25437 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-25437 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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