CVE-2024-50171

What it actually does

The bcm_sysport_xmit function returns NETDEV_TX_OK without freeing the skb when dma_map_single fails, causing a memory leak.

Why it matters to the business

Over time, repeated failures on systems using Broadcom systemport network hardware can lead to gradual memory exhaustion, degrading performance or causing instability in network-intensive deployments.

How an attack unfolds

An attacker triggers packet transmission on an affected Broadcom systemport device under conditions that cause dma_map_single to fail, leaving the skb allocated; listed threat actors have focused on other Linux kernel resource and bounds issues rather than this specific leak path.

How to fix it

Upgrade the Linux kernel to the version containing commit 19583ca584d6f574384e17fe7613dfaeadcdc4a6 which adds the missing dev_kfree_skb call.

How to confirm the fix worked

Inspect the bcm_sysport_xmit function in the updated kernel source to confirm dev_kfree_skb is invoked immediately after a dma_map_single failure.

Typical attack path

1. Locate systems exposing Broadcom systemport network interfaces
2. Induce network transmission that forces dma_map_single failure
3. Observe skb objects accumulating without being freed

How to detect it

Review kernel logs and memory statistics on systems using the bcm_sysport driver for patterns of increasing skb allocations without corresponding frees during DMA-related transmission events.

What your security team should do

• Apply the referenced kernel commit or later stable release across all affected systems
• Prioritize updates on hosts with Broadcom systemport hardware and high network traffic
• Monitor memory usage trends on network drivers and schedule kernel upgrades before resource pressure occurs