CVE-2021-25436

Arbitrary code execution via malformed FOTA input

Published Jul 8, 2021 · Updated Aug 3, 2024

Improper input validation in Samsung Tizen 5.5 FOTA service allows physically proximate attackers to execute arbitrary code. The service accepts a crafted firmware-update file through Samsung Accessory Protocol without adequate validation; Samsung has not disclosed the affected parser or rejected input condition. Exploitation requires physical proximity and user interaction, and successful code execution can take control of the affected watch.

CVSS severity9.8
Critical
EPSS probability1.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper input validation in Samsung Tizen 5.5 FOTA service allows physically proximate attackers to execute arbitrary code. The service accepts a crafted firmware-update file through Samsung Accessory Protocol without adequate validation; Samsung has not disclosed the affected parser or rejected input condition. Exploitation requires physical proximity and user interaction, and successful code execution can take control of the affected watch.

The record

CVE
CVE-2021-25436
Published
Jul 8, 2021
Updated
Aug 3, 2024
Vendor
Samsung Electronics
Product
Tizen
Classifications
CWE-20, T1203
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=Tizen 5.5 <Firmware update JUL-2021 Release

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Samsung Electronics · Tizenversion=Tizen 5.5 <Firmware update JUL-2021 Release

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-20Improper Input Validation
T1203Exploitation for Client Execution

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo