CVE-2023-21420
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 · uneditedUse of Externally-Controlled Format String vulnerabilities in STST TA prior to SMR Jan-2023 Release 1 allows arbitrary 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 · high confidenceThis is an externally-controlled format string vulnerability in the STST Trusted Application (TA). Format string vulnerabilities occur when user-controlled input is passed directly to format string functions (e.g., printf), allowing attackers to read stack memory or write to arbitrary memory locations, leading to arbitrary 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= 10.0= 11.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 STST Trusted Application presenceLocate the STST TA binary or package on the Samsung Android device. This is typically found in the TEE or system trusted application directory.Affected if STST TA is present on the device (vulnerable component exists)
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Retrieve STST TA versionUse system commands or diagnostic tools to query the installed version of the STST Trusted Application. This may require root access or Samsung-specific diagnostic tools.Affected if Version cannot be determined or is older than SMR Jan-2023 Release 1
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Verify TEE/TrustZone is enabledConfirm that the Trusted Execution Environment (TEE) and STST TA are enabled and operational on the device.Affected if TEE and STST TA are actively running on the device
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Compare version against patch levelCompare the installed STST TA version against the fixed version (SMR Jan-2023 Release 1). Any version prior to this release is vulnerable.Affected if Installed version is earlier than SMR Jan-2023 Release 1
The device is affected if it runs Samsung Android 10.0 or 11.0 with STST Trusted Application present and the version is earlier than SMR Jan-2023 Release 1.
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 · scopedUpdate STST TA to SMR Jan-2023 Release 1 or later to obtain the vendor patch that addresses the format string vulnerability.
SMR Jan-2023 Release 1 (January 2023 security patch)
- 1. Navigate to Settings on the Samsung device
- 2. Go to Software Update
- 3. Tap Download and Install to check for available updates
- 4. Ensure the device updates to the January 2023 security patch level (SMR Jan-2023 Release 1) or later
- 5. Verify the update was installed by checking the Android security patch level in Settings > About Phone > Software Information
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-21420 — 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-2023-21420 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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