CVE-2025-48534 Overview
CVE-2025-48534 is a privilege escalation vulnerability in the Android CellBroadcastService component. The flaw resides in the getDefaultCBRPackageName method of CellBroadcastHandler.java. A logic error in this method allows an unprivileged local context to influence package resolution used by the cell broadcast subsystem. According to Google, exploitation can lead to local denial of service with System execution privileges required, but the underlying weakness is categorized as an escalation of privilege issue [CWE-693: Protection Mechanism Failure]. The vulnerability affects Android 13, 14, and 15, and was patched in the September 2025 Android Security Bulletin.
Critical Impact
A logic error in getDefaultCBRPackageName can be abused to bypass intended protection mechanisms in the Android CellBroadcastService, impacting confidentiality, integrity, and availability on affected devices.
Affected Products
- Google Android 13
- Google Android 14
- Google Android 15
Discovery Timeline
- 2025-09-01 - Google releases the September 2025 Android Security Bulletin with the fix
- 2025-09-04 - CVE-2025-48534 published to NVD
- 2025-09-05 - Last updated in NVD database
Technical Details for CVE-2025-48534
Vulnerability Analysis
The vulnerability lives in CellBroadcastHandler.java, part of the Android CellBroadcastService module. The getDefaultCBRPackageName function is responsible for resolving the default Cell Broadcast Receiver (CBR) package that handles emergency and broadcast messages on the device. A logic error in this resolution path allows an attacker with local access to influence which package is treated as the default handler. Because the CellBroadcastService runs with System privileges, downstream calls into the resolved package can be coerced into behavior that the protection mechanism was intended to prevent. Google classifies the outcome as escalation of privilege leading to local denial of service, and notes that user interaction is not required.
Root Cause
The root cause is a protection mechanism failure [CWE-693] in the package-name resolution logic. The function does not adequately validate the candidate package before treating it as the default CBR handler. Reviewing the upstream fix in the Android CellBroadcastService commit shows tighter constraints on how the default package is determined.
Attack Vector
Exploitation requires local access on the device but no user interaction. A malicious local actor can trigger the flawed resolution path in CellBroadcastHandler, causing the System-privileged service to act on an incorrectly resolved package. The result is a denial of service condition in the CellBroadcast pipeline and a bypass of the intended privilege boundary between user-level callers and the System-level service.
No public proof-of-concept exploit is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Technical specifics of the corrected logic are documented in the Android Security Bulletin September 2025.
Detection Methods for CVE-2025-48534
Indicators of Compromise
- Unexpected crashes or restarts of the com.android.cellbroadcastservice process in logcat and bug reports.
- Anomalous resolution of the default Cell Broadcast Receiver package on devices that have not been updated to the September 2025 security patch level.
- Installation of low-reputation applications immediately preceding CellBroadcastService instability.
Detection Strategies
- Inventory Android fleet build fingerprints and flag devices whose ro.build.version.security_patch predates 2025-09-01.
- Use mobile threat defense or MDM telemetry to identify devices running Android 13, 14, or 15 without the September 2025 patch applied.
- Correlate CellBroadcastService crash signatures with recent third-party application installs through endpoint and mobile telemetry pipelines.
Monitoring Recommendations
- Monitor MDM compliance dashboards for security patch level drift on Android 13–15 devices.
- Forward Android device logs and crash reports to a central analytics platform and alert on repeated CellBroadcastService faults.
- Track newly installed packages that declare cell broadcast related intents or permissions on managed devices.
How to Mitigate CVE-2025-48534
Immediate Actions Required
- Apply the September 2025 Android security patch (security patch level 2025-09-01 or later) to all Android 13, 14, and 15 devices.
- Enforce a minimum security patch level policy in MDM and block enrollment of non-compliant devices.
- Restrict sideloading and limit installations to vetted, trusted application sources.
Patch Information
Google addressed CVE-2025-48534 in the September 2025 Android Security Bulletin. The corresponding source change is published in the Android CellBroadcastService commit 584cec4f. Devices reporting ro.build.version.security_patch of 2025-09-01 or later from Google or the device OEM contain the fix. Refer to the Android Security Bulletin September 2025 for OEM coordination details.
Workarounds
- No vendor-supplied workaround exists; patching is the supported remediation.
- Reduce exposure by avoiding installation of untrusted local applications until the patch is applied.
- Apply MDM controls that block installation of applications requesting cell broadcast related capabilities on unpatched devices.
# Verify the Android security patch level on a connected device
adb shell getprop ro.build.version.security_patch
# Expected output for patched devices: 2025-09-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
