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AndroidOperating system · Google

CVE-2021-25478

HIGH · 7.2 CVSS v3.1 Published 2021-10-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
Remotely reachable 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
A possible stack-based buffer overflow vulnerability in Exynos CP Chipset prior to SMR Oct-2021 Release 1 allows arbitrary memory write and code execution.

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 stack-based buffer overflow vulnerability in Samsung's Exynos CP Chipset (baseband/processor component) allows an attacker to write to arbitrary memory locations and achieve code execution due to insufficient bounds checking in the chipset firmware.

MitigationUpdate affected devices to the SMR Oct-2021 Release 1 firmware patch or later, which contains the fix for the Exynos CP Chipset vulnerability.

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
AndroidOperating system
Affected:= 8.1= 9.0= 10.0= 11.0

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/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 your device chipset model
    Check your device specifications or use a system info app to determine if the device uses a Samsung Exynos chipset with baseband/CP (Cellular Processor) component. This is typically found under Settings > About Phone > Chipset or through diagnostic apps.
    Affected if The device uses a Samsung Exynos chipset with CP (baseband) component - non-Exynos devices (like Qualcomm variants) are not affected by this specific vulnerability.
  2. Check your Android OS version
    Go to Settings > About Phone > Android version. Confirm the exact version number.
    Affected if Android version is 8.1, 9.0, 10.0, or 11.0 - only these specific versions listed in the affected products are vulnerable.
  3. Check the baseband/CP firmware version
    On Samsung Exynos devices, check Settings > About Phone > Software information > Baseband version, or use *#0011# or *#1234# diagnostic codes to view CP firmware details. Record the baseband version string.
    Affected if The baseband/CP firmware version is unpatched - the fix was included in the SMR (Samsung Maintenance Release) Oct-2021 Release 1 or later. Compare your baseband version to Samsung's SMR patch releases for your specific model.
  4. Verify Samsung SMR firmware version
    Check Settings > About Phone > Software information > Build number. The SMR (Samsung Maintenance Release) version is typically shown in the build number or can be cross-referenced with Samsung's security bulletins.
    Affected if The SMR version is earlier than Oct-2021 Release 1 for your specific device model - devices on earlier SMR versions remain vulnerable.

A device is affected if it runs Android 8.1, 9.0, 10.0, or 11.0 on a Samsung Exynos chipset with an unpatched baseband/CP firmware version predating the SMR Oct-2021 Release 1.

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

Update affected devices to the SMR Oct-2021 Release 1 firmware patch or later, which contains the fix for the Exynos CP Chipset vulnerability.

Recommended fix High confidence

SMR Oct-2021 Release 1

  1. Apply the October 2021 Samsung Security Maintenance Release (SMR) update to the affected device. This can typically be done by going to Settings > Software update > Download and install, or by checking for system updates.

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

Fix this in Android Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing12.0 h
  • Review / QA6.0 h
38.0 hours of engineering $6,640
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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-2021-25478 in production — separate from our analysis above.

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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