CVE-2025-48535 Overview
CVE-2025-48535 is an unsafe deserialization vulnerability in the Android Settings component, specifically within the assertSafeToStartCustomActivity method of AppRestrictionsFragment.java. The flaw enables a parcel mismatch that attackers can exploit to launch arbitrary activities, resulting in local privilege escalation. Exploitation requires no user interaction and no additional execution privileges beyond a local, low-privileged context. Google addressed the issue in the September 2025 Android Security Bulletin. The vulnerability affects Android versions 13, 14, 15, and 16, spanning a broad segment of the mobile ecosystem.
Critical Impact
A local attacker can escalate privileges by abusing a parcel mismatch to launch arbitrary activities inside a higher-privileged context, without user interaction.
Affected Products
- Google Android 13.0
- Google Android 14.0
- Google Android 15.0 and 16.0
Discovery Timeline
- 2025-09-04 - CVE-2025-48535 published to the National Vulnerability Database
- 2025-09-01 - Fix included in the Android Security Bulletin for September 2025
- 2026-06-17 - Last updated in the NVD database
Technical Details for CVE-2025-48535
Vulnerability Analysis
The vulnerability resides in the AppRestrictionsFragment class inside the Android Settings app. The assertSafeToStartCustomActivity method is intended to validate whether a custom activity can be safely started from a restricted context. A parcel mismatch during deserialization defeats this safety check and enables what Google classifies as a launch-anywhere condition.
Parcel mismatch bugs occur when the data written to a Parcel differs from the data read back, allowing an attacker-controlled Intent to smuggle fields past validation. When the validator inspects one representation of the object and the framework later acts on a different one, an attacker can bypass activity-launch restrictions. The result is local escalation of privilege into the Settings process context.
Root Cause
The root cause is unsafe deserialization [CWE-502] in AppRestrictionsFragment.java. The method reads a nested Intent from a parent Intent bundle, validates properties on the deserialized object, and then passes the original bundle to startActivity. Because Android's Parcelable machinery can produce different results between serialization and deserialization rounds, the validated view of the Intent diverges from the one actually launched.
Attack Vector
A local attacker with the ability to run an unprivileged app on the device crafts a malicious Intent targeting the vulnerable Settings entry point. The crafted payload passes assertSafeToStartCustomActivity but resolves to a different activity when Android dispatches it. This launches an arbitrary activity in the Settings context, allowing the attacker to reach interfaces normally gated by system privileges. No user interaction is required.
Google's upstream fix is available in the Android Settings code change. Refer to the Android Security Bulletin for September 2025 for detailed advisory information.
Detection Methods for CVE-2025-48535
Indicators of Compromise
- Unexpected activity launches originating from com.android.settings shortly after invocations of AppRestrictionsFragment
- Installed applications requesting the BIND_DEVICE_ADMIN or restricted-profile management flows without an obvious administrator use case
- Anomalous Intent extras containing nested Parcelable objects targeting Settings components
Detection Strategies
- Monitor mobile endpoints for applications that construct nested Intent payloads directed at Settings deep links
- Correlate installation of unsigned or sideloaded APKs with subsequent privilege changes to restricted user profiles
- Track Android patch level reporting to identify fleet devices still on pre-September 2025 security patch levels
Monitoring Recommendations
- Enroll Android devices in a mobile threat defense workflow that reports the monthly security patch level per device
- Alert when devices in scope run Android 13 through 16 without the 2025-09-01 patch level
- Review Mobile Device Management (MDM) telemetry for apps abusing restricted profile APIs
Singularity Endpoint protects mobile devices from zero-day malware, phishing, and man-in-the-middle attacks, and can provide the behavioral telemetry needed to identify anomalous app behavior consistent with local privilege escalation attempts.
How to Mitigate CVE-2025-48535
Immediate Actions Required
- Apply the September 2025 Android security patch level or later to all managed Android 13, 14, 15, and 16 devices
- Enforce MDM policies that block installation of untrusted third-party APKs on corporate-managed devices
- Audit devices for compliance with the 2025-09-01 or later security patch level and quarantine non-compliant devices
Patch Information
Google released the fix in the Android Security Bulletin September 2025. The upstream source change is available in the AOSP Settings repository. Device manufacturers ship the fix as part of their monthly patch level updates; end users should install the latest available OTA update from their vendor.
Workarounds
- No official workaround is available; installing the vendor patch is the only supported remediation
- Restrict installation of untrusted applications and disable developer options and USB debugging on production devices
- Use MDM to disable sideloading and enforce Google Play Protect scanning on all managed devices
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
