CVE-2024-42244

What it actually does

Incorrect context pointer in second read URB for mos7840 ports after generic resume path submits multiple URBs, leading to kernel crash on system resume for open ports.

Why it matters to the business

Unexpected system crashes on resume for affected Linux systems using mos7840-based USB serial adapters, causing downtime and potential data loss in environments relying on serial hardware.

How an attack unfolds

An attacker with local access or the ability to trigger suspend/resume cycles on a system with an affected USB serial device connected can cause the kernel to crash by allowing the USB serial core to invoke the generic resume handler, which submits URBs with an invalid port context.

How to fix it

Update the Linux kernel to commit 932a86a711c722b45ed47ba2103adca34d225b33 or later; for AlmaLinux 8 tboot package update to 1:1.10.2-1.el8. Implement dedicated suspend and resume functions in the driver as the permanent fix.

How to confirm the fix worked

Confirm the driver source includes custom suspend/resume handlers and test resume cycles with the Delock 87414 adapter or equivalent mos7840 hardware; verify no crash occurs and busy flag is correctly set.

Typical attack path

1. Identify system using mos7840 USB serial driver with open ports
2. Trigger system suspend and resume cycle
3. Observe kernel crash due to invalid URB context pointer

How to detect it

Review kernel logs for oops or panic messages referencing mos7840, URB submission, or resume paths around suspend events; check dmesg for context pointer mismatches.

What your security team should do

• Prioritize kernel updates on systems with mos7840 USB serial hardware
• Monitor for kernel oops logs during resume events
• Disable unnecessary USB serial devices if updates cannot be applied immediately