CVE-2024-56746

What it actually does

A memory leak occurs in the sh7760fb framebuffer driver because sh7760fb_free_mem() fails to release memory correctly when screen_base information is unavailable; the fix replaces it with direct dma_free_coherent() call.

Why it matters to the business

May lead to gradual memory exhaustion on affected Linux systems using this framebuffer, increasing operational costs or causing crashes in long-running environments. Low exploitability reduces immediate risk.

How an attack unfolds

An attacker with local access could trigger repeated allocations in the driver to exhaust memory, but no public exploits known. Generic kernel threat actors noted but not tied to this issue.

How to fix it

Update the Linux kernel to the fixed commit 0d3fb3b3e9d66f7b6346e3b90bc0ff48683539ce or later versions containing the patch in sh7760fb_alloc_mem().

How to confirm the fix worked

Inspect kernel source for the referenced commit or review sh7760fb_alloc_mem() to confirm dma_free_coherent() is used on the error path.

Typical attack path

1. Obtain local access to a Linux system using the sh7760fb driver
2. Trigger error paths in framebuffer memory allocation
3. Repeat to accumulate leaked memory
4. Cause resource exhaustion or system instability

How to detect it

Review kernel logs for framebuffer allocation failures or warnings; track unusual memory growth in display-related processes.

What your security team should do

• Apply the kernel patch or updated distribution packages containing the fix
• Prioritize systems running the affected framebuffer driver
• Monitor memory usage on long-running Linux hosts