CVE-2023-1855

What it actually does

Use-after-free in xgene_hwmon_remove due to a race condition allows a local process to trigger kernel memory corruption that can crash the system or leak kernel memory contents.

Why it matters to the business

Local users on affected Linux systems can cause denial of service through kernel crashes or potentially expose sensitive kernel data, increasing risk of further attacks on systems that have not been updated.

How an attack unfolds

An attacker with local access loads or interacts with the xgene-hwmon driver in a way that triggers concurrent removal and access operations, exploiting the race to perform a use-after-free that leads to a crash or controlled memory read.

How to fix it

Update the Linux kernel to the fixed commit cb090e64cf25602b9adaf32d5dfc9c8bec493cd1 or later in the torvalds/linux repository; rebuild and deploy the updated kernel across all affected systems.

How to confirm the fix worked

Verify the running kernel contains commit cb090e64cf25602b9adaf32d5dfc9c8bec493cd1 via git log or kernel version strings; attempt to reproduce the race condition in a test environment to confirm the flaw is absent.

Typical attack path

1. Obtain local user access on a system using the xgene-hwmon driver
2. Trigger concurrent hardware monitoring operations and driver removal
3. Exploit the resulting use-after-free to corrupt kernel state
4. Cause kernel panic for denial of service or read kernel memory for information disclosure

How to detect it

Review kernel logs for oops, panic, or use-after-free warnings mentioning xgene-hwmon or drivers/hwmon/xgene-hwmon.c; correlate with unusual local process activity around driver load/unload times.

What your security team should do

• Prioritize kernel updates on all systems exposing the xgene-hwmon driver
• Restrict local unprivileged access where feasible until patches are applied
• Monitor for kernel oops or panic events related to hwmon drivers