CVE-2025-21020
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 · uneditedOut-of-bounds write in creating bitmap images in Blockchain Keystore prior to version 1.3.17.2 allows local privileged attackers to write out-of-bounds memory.
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 confidenceAn out-of-bounds write vulnerability exists in the Blockchain Keystore's bitmap image creation functionality prior to version 1.3.17.2. A local privileged attacker can exploit improper bounds checking during bitmap processing to write memory outside allocated buffer boundaries, potentially leading to memory corruption and code execution.
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< 1.3.17.2CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify if Samsung Blockchain Keystore is installedCheck device or system for the presence of the Samsung Blockchain Keystore application. On Android, this can be done via package manager (adb shell pm list packages | grep -i blockchain) or through device settings under Apps.Affected if The Samsung Blockchain Keystore application is found on the device
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Determine the installed version of Blockchain KeystoreRetrieve the version number of the Samsung Blockchain Keystore app. On Android, use 'adb shell dumpsys package com.samsung.android.knox.analytics.blockchain' or check the app info screen in Settings > Apps > Blockchain Keystore.Affected if The version number returned is lower than 1.3.17.2
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Verify the bitmap image creation functionality is accessibleConfirm that the Blockchain Keystore application has been used or initialized, which would allow access to its bitmap image creation feature. This feature is part of the core keystore functionality used for generating visual representations of keys or transactions.Affected if The application has been initialized or used, enabling access to the bitmap creation functionality
You are affected if Samsung Blockchain Keystore is installed with a version lower than 1.3.17.2 and the application has been used, allowing access to the vulnerable bitmap image creation feature.
Generated from the published advisory. Verify against your own configuration.
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 · scoped1.3.17.2
Upgrade Blockchain Keystore to version 1.3.17.2 or later. Apply principle of least privilege to limit local privileged access and minimize attack surface.
1.3.17.2
- Open the Samsung Galaxy Store or Galaxy Settings on the device
- Navigate to Apps > Blockchain Keystore
- Check the current installed version under App info
- Update Blockchain Keystore to version 1.3.17.2 or later through the Galaxy Store or system update
- Verify the update was successful by checking the app version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-21020 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-21020 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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