CVE-2023-52626

What it actually does

Pointer arithmetic bug in mlx5e port timestamping napi_poll causes postfix increment to apply to the pointer address before dereference, resulting in out-of-bounds memory read.

Why it matters to the business

Systems using affected Linux kernels with MLX5 Ethernet hardware may experience crashes, denial of service, or leakage of kernel memory contents, leading to unplanned downtime and potential data exposure on servers and network appliances.

How an attack unfolds

An attacker with local user privileges crafts network traffic or device interactions that invoke the mlx5e napi_poll routine under conditions triggering the incorrect pointer increment, allowing controlled out-of-bounds reads to access adjacent kernel memory.

How to fix it

Upgrade the Linux kernel to version 6.6.15 or later, or apply the commit 40e0d0746390c5b0c31144f4f1688d72f3f8d790. For Red Hat Enterprise Linux 8.4 EUS systems, update libreswan packages to version 0:4.3-6.el8_4 or newer. Reboot after kernel updates and verify the mlx5e driver is using the patched code.

How to confirm the fix worked

Confirm kernel version is at or above the fixed release, inspect the source for corrected parentheses around the dereference before increment, and test mlx5e timestamping workloads to ensure no out-of-bounds accesses occur.

Typical attack path

1. Obtain local access on a system running an affected kernel with mlx5e driver loaded
2. Trigger port timestamping activity that enters napi_poll context
3. Exploit operator precedence to perform out-of-bounds read
4. Read sensitive kernel memory or cause system instability

How to detect it

Review system logs for unexpected kernel oops or page faults involving mlx5e or napi_poll around the time of timestamping operations; examine crash dumps for out-of-bounds accesses in the mlx5 driver; correlate with local user sessions initiating network activity on affected interfaces.

What your security team should do

• Prioritize kernel upgrades on all systems exposing MLX5 hardware within the next patching cycle
• Monitor vendor advisories for backported fixes in distribution kernels
• Restrict local user privileges where possible until patches are applied
• Include the updated kernel in golden images and automated deployment pipelines