CVE-2022-48627

What it actually does

Memory overlapping copy occurs when deleting a long line in the virtual terminal buffer because scr_memcpyw is optimized to memcpy, which does not safely handle overlapping source and destination buffers, leading to non-deterministic data corruption.

Why it matters to the business

Potential system instability, crashes, or silent data corruption on Linux systems using virtual consoles, increasing operational risk and requiring kernel updates to restore reliability.

How an attack unfolds

An attacker with local access to a virtual terminal triggers deletion of long lines in the buffer, invoking the vulnerable scr_memcpyw path that overlaps memory and may corrupt kernel data when hardware-accelerated memcpy produces inconsistent results.

How to fix it

Update the Linux kernel to a version containing commit c8686c014b5e872ba7e334f33ca553f14446fc29, which replaces scr_memcpyw with scr_memmovew.

How to confirm the fix worked

Confirm the fix is present by inspecting the vt buffer code for use of scr_memmovew instead of scr_memcpyw, and test terminal deletion operations for stability.

Typical attack path

1. Obtain local shell or console access on a vulnerable Linux kernel
2. Perform repeated line deletion operations in a virtual terminal to trigger buffer handling
3. Leverage resulting memory corruption for denial of service or further exploitation

How to detect it

Review kernel logs and dmesg for oops or panic messages involving vt buffer or console memory operations; no specific post-exploitation artifacts are known.

What your security team should do

• Apply the referenced kernel commit or newer stable releases across all affected systems
• Prioritize updates on servers and devices exposing virtual consoles
• Monitor kernel logs for vt-related panics during the update rollout