CVE-2024-44951

What it actually does

The flaw is a race condition in the sc16is7xx serial driver where EFR locking was changed from chip-wide to per-channel, allowing concurrent access to a shared Tx/Rx data buffer; this corrupts transmit FIFO contents on one channel with receive data from another when operations overlap.

Why it matters to the business

Systems using affected serial hardware may suffer unreliable or corrupted serial communications, leading to device malfunctions, data loss, or operational failures in embedded or industrial setups that depend on accurate multi-channel serial transfers.

How an attack unfolds

An attacker with local or hardware-level access to the sc16is7xx chip sends serial traffic timed so a receive packet arrives on channel A nearly simultaneously with a transmit on channel B; the missing shared-buffer protection lets receive data overwrite the transmit buffer, corrupting outgoing packets.

How to fix it

Upgrade the Linux kernel to a version containing commit 0dd3ee31125508cd67f7e7172247f05b7fd1753a, which switches sc16is7xx_handle_tx to kfifo_out_linear_ptr and allocates separate per-channel Rx buffers.

How to confirm the fix worked

Confirm the applied kernel tree contains the fixing commit or the updated sc16is7xx driver source using kfifo_out_linear_ptr and per-channel Rx buffers; test serial traffic under concurrent RX/TX loads to verify absence of cross-channel corruption.

Typical attack path

1. Locate Linux systems exposing the sc16is7xx driver with multi-channel serial hardware
2. Generate concurrent RX and TX operations across channels via crafted serial input
3. Trigger the race to corrupt TX FIFO contents and observe or leverage resulting communication errors

How to detect it

Review kernel logs and dmesg output around serial activity for sc16is7xx driver anomalies or unexpected FIFO behavior; correlate with application-level serial errors indicating data corruption.

What your security team should do

• Apply the kernel fix containing commit 0dd3ee31125508cd67f7e7172247f05b7fd1753a on all hosts with sc16is7xx hardware
• Audit serial device configurations and disable multi-channel use where feasible until patched
• Add kernel build and boot-time checks to detect vulnerable driver versions