CVE-2024-40934

What it actually does

Memory leak on the error path of logi_dj_recv_send_report() inside logi_dj_recv_switch_to_dj_mode() in the Logitech HID driver, allowing repeated allocation without corresponding free when the send operation fails.

Why it matters to the business

Local users on systems using Logitech Unifying receivers can trigger gradual kernel memory exhaustion leading to reduced availability or crashes; widespread exposure across Linux distributions increases operational risk for any environment running affected kernels.

How an attack unfolds

An attacker with local access repeatedly triggers the error path in the Logitech DJ receive switch function by forcing send_report failures, accumulating leaked kernel memory until resource limits are reached or the system becomes unstable.

How to fix it

Upgrade the Linux kernel to a fixed version such as 5.4.279 or later stable releases containing commit 3c409813f14722c2290c7854f555599d9720d4d4 or 15122dc140d82c51c216535c57b044c4587aae45; apply vendor-supplied updates promptly given the broad ecosystem reach of the kernel.

How to confirm the fix worked

Verify the running kernel version is at or above the listed fixed releases; inspect the HID logitech-dj driver source for the corrected error path handling; test by exercising the switch_to_dj_mode function under error conditions and confirming no net memory growth.

Typical attack path

1. Obtain local user access on a Linux system with Logitech DJ hardware or driver loaded
2. Craft conditions that cause logi_dj_recv_send_report to fail inside logi_dj_recv_switch_to_dj_mode
3. Repeat the triggering sequence to induce repeated allocations without frees
4. Monitor for kernel memory pressure or OOM conditions

How to detect it

Review kernel logs for repeated failures in logi_dj_recv_send_report or logi_dj_recv_switch_to_dj_mode; monitor slab or kmalloc accounting for growth attributable to the HID Logitech driver; correlate with local user activity on systems containing Logitech Unifying hardware.

What your security team should do

• Prioritize kernel updates on all systems exposing Logitech HID devices or running affected versions
• Harden local access controls and monitor for unusual memory usage patterns on multi-user systems
• Include the fixed commits in patch management and vulnerability scanning baselines