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AndroidOperating system · Google

CVE-2021-25516

HIGH · 7.5 CVSS v3.1 Published 2021-12-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
An improper check or handling of exceptional conditions in Exynos baseband prior to SMR Dec-2021 Release 1 allows attackers to track locations.

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 · high confidence

This vulnerability exists in Samsung Exynos baseband firmware prior to SMR Dec-2021 Release 1. The baseband processor (cellular modem) has improper exception handling that can leak location information, allowing remote attackers to track device location without user awareness.

MitigationApply the SMR Dec-2021 Release 1 or later security patch from Samsung to affected devices. This is a baseband firmware update that must be delivered through vendor software 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
AndroidOperating system
Affected:= 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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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 Exynos baseband processor
    Check your device's baseband/modem chipset. On Android, go to Settings > About Phone > Baseband version, or run 'getprop gsm.version.baseband' via ADB shell. Also check 'getprop ro.hardware' or 'cat /proc/cpuinfo' for Exynos references.
    Affected if Device uses Samsung Exynos baseband processor (modem chipset)
  2. Verify Android version
    Go to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADB shell.
    Affected if Android version is 9.0, 10.0, or 11.0
  3. Check baseband firmware version
    Retrieve the baseband firmware version from Settings > About Phone > Baseband version, or run 'getprop gsm.version.baseband' or 'AT+CGMR' (if AT command access is available).
    Affected if Baseband firmware version is before SMR Dec-2021 Release 1 (the specific version string varies by device; look for any date/version prior to December 2021)
  4. Confirm firmware update status
    Check if the device has received Samsung security updates. Go to Settings > About Phone > Software update > Check for updates, or run 'getprop ro.build.version.security_patch' via ADB shell to see the security patch level.
    Affected if Security patch level is earlier than December 2021

Device is affected if it uses a Samsung Exynos baseband processor with firmware prior to SMR Dec-2021 Release 1, running Android 9.0, 10.0, or 11.0, and has not received the December 2021 security patch.

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

Apply the SMR Dec-2021 Release 1 or later security patch from Samsung to affected devices. This is a baseband firmware update that must be delivered through vendor software updates.

Recommended fix High confidence

Update to Samsung SMR Dec-2021 Release 1 (December 2021 security patch level)

  1. Verify your device model uses an Exynos chipset (varies by region - check Settings > About Phone > Baseband)
  2. Check your current security patch level in Settings > About Phone > Software Information > Security patch level
  3. If the security patch level is earlier than December 2021, navigate to Settings > Software Update
  4. Tap 'Download and install' to check for available updates
  5. Apply the December 2021 Samsung Security Update (SMR Dec-2021 Release 1) which contains the fix for this vulnerability
  6. Verify the security patch level now shows December 2021 or later after the update completes
Caveat Security updates typically have no breaking changes; ensure sufficient battery before updating

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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Scan for this in your stack

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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-2021-25516 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