Yes. CISA added CVE-2021-25337 to its Known Exploited Vulnerabilities catalogue on 8 November 2022, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. Samsung mobile devices contain an improper access control vulnerability in clipboard service which allows untrusted applications to read or write arbitrary files.
How KEV Listing Changes the Answer From “Possible” to “Confirmed Exploitation”
CISA’s KEV catalogue is the key operational signal here because it separates a theoretical flaw from one with evidence of active abuse. For defenders, the practical question is not whether the issue exists, but whether the affected Samsung mobile fleet is still exposed and whether any untrusted app on those devices could have used clipboard-service access to touch files it should not reach.
That is why CISA’s inclusion matters more than the CVE label alone: it tells you to treat the issue as an exploitation problem, not a documentation problem. On mobile estates, that changes triage from “plan a patch” to “confirm exposure, constrain risky app behaviour, and check whether device data handling assumptions were already broken.”
When a vulnerability reaches KEV, the investigation should begin with fleet inventory and app trust boundaries. If you cannot quickly tell which Samsung devices are in scope, which OS builds are present, and whether untrusted apps can interact with the clipboard service, you do not yet have a reliable exposure assessment.
What Improper Access Control in a Clipboard Service Means in Practice
An improper access control flaw in a clipboard service is dangerous because clipboard functions often sit close to user convenience and far from user scrutiny. If an untrusted application can read or write arbitrary files through that path, the impact can extend beyond clipboard contents into broader local data exposure, tampering, or privilege abuse inside the device’s trust boundary.
In practical terms, this kind of weakness is usually exploited through app-level abuse rather than dramatic device takeover. The attacker does not need to announce itself if it can look like an ordinary mobile app while quietly using a high-value OS service as a shortcut to data it should not see or alter.
For mobile defenders, that means the relevant control question is whether the platform enforces a clean boundary between user-facing convenience features and file or content access. If the boundary is weak, a seemingly narrow flaw can become a general-purpose local exposure mechanism.
Mobile Device Security Guide is useful here because exposure on smartphones is rarely just about one app or one bug, it is about the managed-device posture, app controls, and whether risky software can coexist with corporate data.
Device Trust and Posture Guide helps connect the vulnerability to real operating conditions, including whether posture checks and managed-device policies would have reduced the chance that an unsafe app remained trusted long enough to exploit the flaw.
What to Do If You Cannot Patch Samsung Devices Immediately
If patching cannot happen at once, the priority is to narrow the exposed surface rather than wait for the next maintenance window. That means reviewing which Samsung devices are in scope, which apps are permitted, and whether any of those apps are untrusted, unmanaged, sideloaded, or unnecessary for business use.
Where mobile device management is available, use it to remove or quarantine risky apps, tighten app approval, and enforce stronger device compliance checks. If the device is unmanaged, the incident response posture should be more conservative because you have fewer ways to prove the clipboard path is not being abused.
Also treat file access and sensitive data handling as part of the response, not a separate issue. If the flaw could expose arbitrary files, then the question is not only whether the device is compromised now, but whether cached documents, tokens, notes, or internal content may already have been read or modified.
Vulnerability Management Guide fits this case well because it emphasises scope, prioritisation, exception handling, and verification when an issue is already known to be exploited.
Zero-Day and Exploited Vulnerabilities Guide is the right companion for emergency triage, since KEV-listed issues should move through a faster response path than ordinary backlog work.
Risk and Threat Considerations
When an exploited mobile vulnerability touches file access, the main risk is silent data exposure or manipulation on devices users still trust. The threat is especially relevant in environments where employees install third-party apps, mix personal and work usage, or rely on mobile devices to open and move sensitive content.
Failure mechanism: An untrusted app abuses weak clipboard-service access checks to read or write files outside its intended boundary, turning an ordinary mobile feature into a local privilege and data-access shortcut.
Impact: Sensitive files can be exposed, altered, or staged for later abuse, and defenders may not notice quickly because the activity can resemble normal app behaviour on an otherwise functioning device.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 addresses the attack and risk surface, while CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | KEV-listed exploitation requires timely identification and remediation of affected devices. |
| Recommendation — Prioritise and remediate the exposed Samsung devices as an active vulnerability management issue. | ||
| NIST CSF 2.0 | DE.CM-01 — Networks and assets are monitored to find cybersecurity events | Confirming exposure depends on monitoring the mobile fleet and detecting suspicious app behaviour. |
| Recommendation — Monitor Samsung device activity and app behaviour for signs of abuse on affected endpoints. | ||
| OWASP Non-Human Identity Top 10 | NHI-05 — Overprivileged NHI | The flaw is fundamentally an access-control failure that permits more file access than intended. |
| NHI-06 — Insecure Cloud Deployment Configurations | Not selected | |
| NHI-10 — Human Use of NHI | Not selected | |
| Recommendation — Reduce the permissions and trust granted to apps that can reach sensitive device services. | ||
Practitioner Guidance
What to verify: Confirm the Samsung device inventory, OS coverage, and app trust model first. If you cannot map devices to owners, managed status, and permitted applications, you cannot reliably judge whether the exploit path is still open.
Decision rule: If a device can run untrusted or poorly governed apps and can also access sensitive business data, treat it as a higher-risk endpoint until the affected software is remediated or the device is removed from use.
Practitioner takeaway: KEV listing should shift this from “known vulnerability” to “active exposure management”, with fleet visibility, app governance, and data-loss review taking priority over routine patch scheduling.
Related resources from NHI Mgmt Group
- CVE-2021-25337 (Samsung Mobile Devices Improper Access Control)
- CVE-2021-25369 (Samsung Mobile Devices Improper Access Control)
- Is CVE-2021-25394 (Samsung Mobile Devices Race Condition) being exploited in the wild?
- Is CVE-2025-21043 (Samsung Mobile Devices Out-of-Bounds Write) being exploited in the wild?