Attack Chain

1. An attacker executes a local, user-level binary on the target Android device.
2. The exploit triggers a vulnerability in the Adreno GPU driver (CP_SET_DRAW_STATE).
3. The GPU driver performs an unauthorized SMMU table update (CP_SMMU_TABLE_UPDATE).
4. The attacker achieves arbitrary physical write primitive via a forged page table.
5. The kernel memory is patched to disable kptr_restrict and modify cap_bprm_creds_from_file to preserve capabilities across binary execution.
6. A resident root daemon is spawned, granting full 41-bit capabilities (CapEff) while maintaining euid=2000 to evade anti-root detection.
7. The daemon provides a command execution interface for arbitrary root commands.

Impact

Successful exploitation allows local, unprivileged users or malicious applications to gain full kernel-level capabilities on affected Android devices, bypassing system security policies and manufacturer-specific anti-root protections. The exploit is resident in RAM and does not persist across reboots, but provides full system control while active.

Recommendation

• Monitor for unauthorized binaries being pushed to /data/local/tmp via ADB or other vectors.
• Audit device integrity for signs of active kernel memory modification, particularly those targeting kptr_restrict or capability-related functions.
• Prioritize patching Android devices when OEM firmware updates addressing CVE-2025-21479 become available.
• Restrict ADB access and developer options in production/managed environments to mitigate the initial deployment vector.