CVE-2024-42066

What it actually does

Integer overflow in min_page_size calculation when tbo->page_alignment is bit-shifted without an explicit u64 cast, allowing an oversized or incorrect page size value to be assigned.

Why it matters to the business

Potential system instability or denial of service in Linux graphics subsystems on affected kernels, increasing operational risk for organizations running Xe-based hardware until patched.

How an attack unfolds

A local attacker triggers the page size calculation path in the Xe driver, causing the uncast shift to produce an invalid value that leads to memory handling failures and a crash or hang.

How to fix it

Update the Linux kernel to a version containing commit 79d54ddf0e292b810887994bb04709c5ac0e1531 which adds the explicit u64 cast before the shift operation.

How to confirm the fix worked

Verify the presence of the u64 cast in the page size calculation code or confirm the running kernel includes commit 79d54ddf0e292b810887994bb04709c5ac0e1531.

Typical attack path

1. Obtain local user access on a Linux system using the affected Xe driver
2. Invoke operations that exercise tbo page alignment and min_page_size assignment
3. Trigger the integer overflow via the missing u64 cast during bit shift
4. Cause driver or kernel instability resulting in availability impact

How to detect it

Review kernel logs for Xe driver crashes or page size related faults around the time of suspected exploitation; correlate with processes using graphics acceleration.

What your security team should do

• Prioritize kernel updates to the fixed commit across all affected systems
• Monitor upstream stable kernel releases for backports of the fix
• Restrict local access where feasible until patches are deployed