CVE-2025-48623 Overview
CVE-2025-48623 is an out-of-bounds write vulnerability in the init_pkvm_hyp_vcpu function of pkvm.c in the Android kernel. The flaw stems from improper input validation in the protected Kernel-based Virtual Machine (pKVM) hypervisor initialization path. A local attacker with low privileges can trigger the condition without user interaction, leading to local privilege escalation. Google addressed the issue in the Android Security Bulletin December 2025.
Critical Impact
Local privilege escalation from a low-privileged context to kernel or hypervisor-level execution, with high impact to confidentiality, integrity, and availability.
Affected Products
- Google Android (kernel component, pKVM subsystem)
- Devices running Android kernels containing the vulnerable pkvm.c implementation prior to the December 2025 patch level
- Arm64-based Android devices leveraging protected KVM for virtualization
Discovery Timeline
- 2025-12-08 - CVE-2025-48623 published to the National Vulnerability Database (NVD)
- 2025-12-01 - Google publishes fix in the Android Security Bulletin
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-48623
Vulnerability Analysis
The vulnerability resides in init_pkvm_hyp_vcpu, a routine responsible for initializing a hypervisor-side virtual CPU (vCPU) structure in Android's protected KVM implementation. Protected KVM isolates guest virtual machines from the host kernel, and vCPU initialization runs in the elevated EL2 hypervisor context. Improper validation of caller-supplied inputs allows a write past the bounds of an allocated buffer or structure.
The weakness is classified as [CWE-787] Out-of-Bounds Write and [CWE-20] Improper Input Validation. Because the write occurs during hypervisor state setup, corrupted memory can influence privileged data structures used by pKVM.
Root Cause
The root cause is missing or insufficient validation of index or size parameters used during init_pkvm_hyp_vcpu execution. When an attacker-controlled value flows into a memory write operation without bounds checking, the routine writes outside the intended region. The patched implementations in Android kernel commits 3b6fab0 and e76cff4 introduce the input validation needed to prevent the out-of-bounds condition.
Attack Vector
Exploitation requires local access with low privileges on the device. A malicious application or compromised process invokes the vulnerable pKVM initialization path and supplies crafted inputs that pass through to init_pkvm_hyp_vcpu. No user interaction is required. Successful exploitation corrupts memory in the hypervisor context, enabling local privilege escalation without additional execution privileges.
No public proof-of-concept exploit code is available for this vulnerability. Refer to the Android kernel commits for details on the fix implementation.
Detection Methods for CVE-2025-48623
Indicators of Compromise
- Unexpected process crashes, kernel panics, or hypervisor faults referencing pkvm or kvm_arm subsystems in device logs
- Applications invoking KVM ioctl interfaces from unprivileged contexts on devices that do not typically run virtualization workloads
- Presence of unsigned or unknown applications requesting hypervisor-related capabilities
Detection Strategies
- Verify the Android security patch level on managed devices and flag any device below the 2025-12-01 patch level as vulnerable.
- Use Mobile Device Management (MDM) attestation to confirm that fleet devices are running kernels containing commits 3b6fab0 and e76cff4.
- Monitor mobile endpoint telemetry for anomalous process activity that references KVM device nodes such as /dev/kvm.
Monitoring Recommendations
- Ingest Android device logs and MDM compliance data into a centralized analytics platform to track patch status across the fleet.
- Alert on installation of applications from untrusted sources on devices missing the December 2025 patch.
- Correlate kernel oops or panic reports with recent application installations to identify potential exploitation attempts.
How to Mitigate CVE-2025-48623
Immediate Actions Required
- Apply the Android security patch level 2025-12-01 or later on all affected devices.
- Prioritize patching for Arm64 devices that use protected KVM, including Google Pixel and other vendors shipping pKVM-enabled kernels.
- Restrict sideloading and enforce application allowlists through MDM policies until patches are deployed.
Patch Information
Google released fixes in the Android Security Bulletin December 2025. The corresponding kernel changes are available in Android kernel commits 3b6fab0 and e76cff4. Device manufacturers must integrate these commits and ship updated firmware images through their standard over-the-air update channels.
Workarounds
- No official workarounds exist. Applying the vendor patch is the only supported remediation.
- Limit exposure by removing untrusted applications and enforcing Google Play Protect scanning on managed devices.
- Enforce MDM compliance rules that quarantine devices running kernels below the December 2025 security patch level.
# Verify the Android security patch level on a device via ADB
adb shell getprop ro.build.version.security_patch
# Expected output for patched devices: 2025-12-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
