Executive brief
A vulnerability in the Linux kernel's I2C device driver could allow a local user to crash the system or cause hardware communication failures. By providing a specially crafted timeout value to the system, an attacker can corrupt the internal state of the SMBus controller. This results in a local denial of service, potentially requiring a system reboot to recover hardware functionality.
Technical details
An integer overflow exists in `drivers/i2c/i2c-dev.c` within the `I2C_TIMEOUT` ioctl handler. The user-provided argument is checked against `INT_MAX`, but is subsequently multiplied by 10 to convert 10ms units to milliseconds before being passed to `msecs_to_jiffies()`. A large input (e.g., 429496729) passes the initial check but overflows during multiplication, resulting in a truncated value that is reinterpreted as a negative signed 32-bit integer. When this value is passed to `wait_for_completion_timeout()`, sign extension occurs, leading to a massive 64-bit unsigned timeout, triggering kernel warnings and leaving the SMBus state machine in an unrecoverable state. The fix bounds the user argument to `INT_MAX / 10`.
Affected products
- Linux Linux Kernel All versions prior to fixed stable releases (e.g., 6.1, 6.6, 6.9)
Timeline
- 2026-04-27: other: Vulnerability reported by Mingyu Wang
- 2026-05-04: patched: Initial patch committed to mainline kernel
- 2026-06-24: advisory: CVE-2026-52948 published
References
- https://git.kernel.org/stable/c/0b88ecfbc9dc33b4db8836c37b50cf174e6c0691
- https://git.kernel.org/stable/c/4576621dc6577f21a032acfd16c3ad61907a5ea7
- https://git.kernel.org/stable/c/617eb7c0961a8dfcfc811844a6396e406b2923ea
- https://git.kernel.org/stable/c/943e318eedbeaeea08ece3f5dd44c982f4ed2ef5
- https://git.kernel.org/stable/c/aa6ef734016912653a909477fb30aeb66c98b3a2
- https://git.kernel.org/stable/c/e9ffd5f5050fbb199d270a85614cd27ebed6fbac
- https://git.kernel.org/stable/c/ff02add34ffd03449b8115904ebe2ec4fed022d4