CVE-2022-48696

What it actually does

Failure to reserve space for register address and padding bytes in regmap_spi max_raw_read and max_raw_write calculations allows SPI messages to exceed the controller's permitted size, resulting in undefined behavior such as data corruption or transfer failures.

Why it matters to the business

Systems using SPI-connected devices on affected kernels risk silent data corruption or device communication failures, potentially disrupting hardware-dependent operations until kernels containing the fix are deployed.

How an attack unfolds

An attacker with the ability to trigger or influence SPI register accesses on a vulnerable system could cause oversized messages to be constructed, leading to memory corruption or transfer errors during regmap operations; no widespread exploitation or named threat actors have been observed.

How to fix it

Update to a Linux kernel containing commit 15ff1f17847c19174b260bd7dd0de33edcebd45e or later; rebuild and deploy the updated kernel on all affected systems.

How to confirm the fix worked

Confirm the running kernel source contains commit 15ff1f17847c19174b260bd7dd0de33edcebd45e and verify that regmap_get_spi_bus() correctly adjusts max_raw_read and max_raw_write for address and padding overhead.

Typical attack path

1. Identify or control a process that performs regmap SPI reads or writes on the target system
2. Craft register access patterns that include address and padding overhead exceeding the unadjusted max_raw limits
3. Trigger the transfer to exceed the SPI controller message size
4. Observe or induce undefined behavior such as data corruption or system instability

How to detect it

Examine kernel logs for SPI message size warnings or regmap transfer errors; no specific pre-fix exploitation artifacts are known.

What your security team should do

• Prioritize kernel updates on any systems using SPI-based regmap devices
• Review SPI device drivers and hardware configurations for exposure
• Monitor for post-update stability in SPI-dependent subsystems