Executive brief
A vulnerability in the bootloader's printf function could allow a local attacker with system-level privileges to write data outside memory boundaries, potentially leading to privilege escalation. This affects Google Pixel devices and could undermine the security protections of the bootloader, the firmware component responsible for safely starting the device.
Technical details
An out-of-bounds write vulnerability exists in the printf.c implementation within the bootloader due to improper input validation. The vulnerability is triggered when printf processes specially crafted format strings or input, allowing an attacker to write beyond allocated buffer boundaries. Exploitation requires System execution privileges on the local system and does not require user interaction. A successful exploit could lead to elevation of privilege within the bootloader environment. The issue was patched in the September 2026 security update (patch level 2026-09-05) for all supported Pixel devices.
Affected products
- Google Pixel Bootloader
Timeline
- 2026-09-15: disclosed
- 2026-09-05: patched