CVE-2024-50208

What it actually does

Invalid memory access and potential corruption when configuring Level-2 PBL pages for non-MR resources with num_pages exceeding 256K due to incorrect assumption of multiple PDE pages instead of a single contiguous address.

Why it matters to the business

Kernel instability or crashes on systems using bnxt_re RDMA hardware with large page table configurations, leading to service disruption and possible local privilege escalation in affected Linux environments; low downstream prevalence limits widespread operational risk.

How an attack unfolds

An attacker with local access crafts a scenario that triggers PBL page setup exceeding 256K entries for non-MR resources, causing the driver to perform invalid memory writes or reads beyond the intended PDE page boundary.

How to fix it

Upgrade the Linux kernel to commit df6fed0a2a1a5e57f033bca40dc316b18e0d0ce6 or later stable releases containing the fix; apply vendor backports for supported distributions and verify the bnxt_re module is updated.

How to confirm the fix worked

Confirm the kernel source contains the patch resolving the single PDE page logic; test resource allocation paths with num_pages > 256K under the bnxt_re driver and monitor for memory corruption indicators.

Typical attack path

1. Obtain local code execution or user privileges on a Linux system with bnxt_re RDMA driver loaded
2. Allocate or request non-MR resources requiring more than 256K PBL entries
3. Trigger the Level-2 PBL page setup path in the driver
4. Exploit resulting out-of-bounds memory access for corruption or crash

How to detect it

Inspect kernel logs for bnxt_re driver errors or oops messages during resource allocation; review system call traces involving RDMA page table setup for unusually large page counts.

What your security team should do

• Prioritize kernel updates on systems exposing RDMA interfaces or using bnxt_re hardware
• Review and restrict unprivileged access to RDMA device nodes where feasible
• Monitor EPSS and KEV status for any future increase in exploit activity