CVE-2021-25395 is a race condition vulnerability in Samsung Mobile Devices. CISA added it to the Known Exploited Vulnerabilities catalogue on 29 June 2023, which means attackers have used it in real attacks. Samsung mobile devices contain a race condition vulnerability within the MFC charger driver that leads to a use-after-free allowing for a write given a radio privilege is compromised.
What the vulnerability is and why it matters
CVE-2021-25395 is a race condition in Samsung Mobile Devices, specifically in the MFC charger driver. A race in driver state handling is dangerous because timing gaps can turn a memory-safety bug into a controllable write primitive, which is why this class of flaw often becomes a route to privilege escalation or device compromise.
For a CVE like this, the most important takeaway is not just that the bug exists, but that exploitation depends on the exact product state, firmware build, and runtime conditions. Treat the vendor advisory and the CVE Program record as the authoritative starting point for record details, while the NIST National Vulnerability Database is the place to cross-check the published vulnerability entry.
How organisations determine exposure
Exposure checks start with an asset inventory that can answer a simple question: which Samsung mobile devices are in use, who owns them, and which software builds are installed. That inventory should be paired with mobile device management data, because unmanaged or partially managed devices are where vulnerability visibility tends to break down.
The practical risk question is whether vulnerable devices are still reachable in the fleet, including employee-owned handsets enrolled for work use. The Mobile Device Security Guide is useful here because it frames the operational controls around enrolment, compliance, and fleet visibility. For broader weakness tracking, the CWE Top 25 Guide helps place race conditions in the wider memory-safety landscape, including use-after-free style failure modes.
Remediation and compensating controls
When a patch is available, remediation should be driven by the vendor advisory and prioritised according to exposure, not just convenience. If immediate patching is not possible, organisations should reduce attack surface by restricting device exposure to untrusted networks, tightening mobile policy enforcement, and limiting any workflow that could trigger the vulnerable driver path.
The broader lesson from exploited mobile vulnerabilities is that compensating controls matter most when the device is business critical or patch rollout lags. The Vulnerability Management Guide is relevant because it ties KEV presence to prioritisation, exception handling, and verification rather than treating every patch as equal. In mobile environments, that means pairing vendor guidance with fleet policy decisions and rapid enforcement through MDM or equivalent controls.
Detection and post-exploitation review
Race conditions are hard to spot from a single event, so detection usually depends on seeing the aftermath: crashes, abnormal driver behaviour, unexplained reboots, or signs that the device state has been altered in ways that do not match normal charging or radio activity. Because the primary risk is a write primitive, post-exploitation review should assume the attacker may have moved from a vulnerability into broader device control.
That review should include logs from mobile management systems, any available endpoint telemetry, and a check for unusual configuration drift or persistence mechanisms. If there is any reason to suspect exploitation, treat the device as potentially untrusted until it has been reimaged or otherwise validated by your mobile security process.
Risk and Threat Considerations
Exploited mobile-device races are dangerous because they can turn a low-level timing flaw into reliable privilege abuse on a widely deployed endpoint. Once attackers can influence the vulnerable code path, the impact is not limited to a crash, it can become a stepping stone to deeper compromise of the handset and the data it handles.
Failure mechanism: A race condition allows one execution path to invalidate or free state while another path still assumes it is valid, creating a use-after-free and a potential write primitive.
Impact: Attackers may use that primitive to gain higher privileges, tamper with device integrity, or extend compromise beyond the original application boundary.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8, NIST SP 800-53 Rev 5 and OWASP ASVS set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | CVE exposure and KEV status require ongoing vulnerability tracking and prioritisation. |
| CIS-1 — Inventory and Control of Enterprise Assets | Exposure depends on whether Samsung mobile devices are present and managed in the environment. | |
| Recommendation — Prioritise and verify remediation for KEV-listed Samsung devices through continuous vulnerability management. Maintain an accurate device inventory so vulnerable Samsung endpoints can be identified quickly. | ||
| NIST SP 800-53 Rev 5 | RA-5 — Vulnerability Monitoring and Scanning | The term concerns identifying exposure to a known exploited vulnerability across an asset fleet. |
| SI-2 — Flaw Remediation | The vulnerability requires timely patching, exception handling, and validation after remediation. | |
| Recommendation — Scan managed devices, confirm exposure, and track remediation status for the affected Samsung fleet. Apply flaw remediation controls to patch affected devices and validate that the weakness is closed. | ||
| OWASP ASVS | V15 — Secure Coding and Architecture | The root issue is a race condition and use-after-free class weakness in a device driver. |
| Recommendation — Review concurrency-sensitive code paths to prevent race conditions from becoming memory-safety flaws. | ||
Practitioner Guidance
Why practitioners should care: This kind of CVE is a fleet problem, not just a single-device bug. If Samsung mobile devices are used for business access, the issue becomes an endpoint assurance and incident-response concern as much as a patching task.
What to watch for: Prioritise devices that are internet-reachable, carry sensitive work data, or are enrolled in high-trust mobile workflows. Any signs of instability, unexplained reboots, or security-policy drift after exposure should trigger review and containment.
Practitioner takeaway: Use the vendor advisory for version details, use KEV status to drive urgency, and treat post-patch validation as mandatory if the device may already have been exposed.
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Reviewed and updated by the NHIMG editorial team on October 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org