Security readout for executives and security teams
Plain-English summary
CVE-2021-25396 affects Samsung Mobile Devices running Android Q(10.0) or R(11.0) before Samsung's May 2021 security maintenance release. It is a local, high-privilege flaw in NPU firmware input validation that could allow memory corruption and code execution. Business urgency is moderate unless vulnerable, unmanaged devices remain in production.
Executive priority
Treat this as a moderate mobile fleet hygiene issue. It is not sourced as actively exploited, but unpatched legacy Samsung devices could face serious impact if an attacker already has privileged local access.
Technical view
The CVE describes improper input validation in Samsung NPU firmware, mapped to CWE-787. The CVSS 3.1 vector is AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, scoring 6.7. The impact is potentially severe after local privileged access, but the privilege requirement materially limits broad remote exploitation.
Likely exposure
Exposure is limited to Samsung Mobile Devices on Android Q(10.0) or R(11.0) that did not receive SMR MAY-2021 Release 1 or later. Organizations with BYOD, unmanaged Android fleets, or legacy Samsung devices should verify patch status.
Exploitation context
The provided sources do not indicate active exploitation, and the CVE is not listed as KEV in the bundle. Exploitation requires local access and high privileges, with no user interaction. If those prerequisites are met, the confidentiality, integrity, and availability impact is high.
Researcher notes
Public detail is sparse. The reliable facts are vendor, affected Android generations, NPU firmware input validation, CWE-787, CVSS vector, and the Samsung May 2021 SMR reference. Avoid assuming reachable attack surfaces or exploit primitives beyond arbitrary memory write and code execution stated by the CVE.
Mitigation direction
- Apply Samsung SMR MAY-2021 Release 1 or later where available.
- Check Samsung Mobile security guidance for model-specific update availability.
- Remove or isolate unsupported Samsung devices that cannot receive security updates.
- Enforce mobile device management compliance for minimum Android security patch level.
Validation and detection
- Inventory Samsung Mobile Devices running Android Q(10.0) or R(11.0).
- Verify each device's Android security patch level against Samsung May 2021 guidance.
- Use MDM reports to identify noncompliant or unsupported Samsung devices.
- Confirm remediation through post-update device compliance status.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-25396 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://security.samsungmobile.com/securityUpdate.smsb?year=2021&month=5CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.