CVE-2021-47015 is a vulnerability identified in the Linux kernel's Broadcom NetXtreme (bnxt) network driver, specifically in the RX (receive) packet processing logic. The vulnerability arises from incorrect handling of the RX consumer index in the error path within the bnxt_rx_pkt() function. Normally, RX buffers are expected to complete in order, and the RX consumer index tracks this progress. However, when an out-of-order buffer completion occurs—indicative of a hardware bug—the driver attempts to abort all remaining RX packets and reset the RX ring. The flaw is that the driver passes an outdated consumer index (raw_cons) to the bnxt_discard_rx() function instead of the current index (tmp_raw_cons). This mismatch can cause the driver to reference incorrect memory locations when aborting packets, leading to a kernel crash (panic) or oops due to invalid memory access. The crash stack trace shows faults occurring during page fault handling in the kernel, triggered at the bnxt_rx_pkt function. This vulnerability is a logic error in the network driver’s error recovery path, which can cause denial of service through kernel crashes. The affected versions include multiple Linux kernel commits identified by their hashes, indicating the bug existed across several kernel versions before being fixed. There are no known exploits in the wild, and no CVSS score has been assigned yet. The vulnerability does not appear to allow privilege escalation or remote code execution directly but can cause system instability and downtime due to kernel panics triggered by network hardware anomalies or maliciously crafted network traffic that triggers the error path.

For European organizations, the impact of CVE-2021-47015 primarily involves potential denial of service (DoS) conditions on Linux systems using affected Broadcom NetXtreme network drivers. This can lead to unexpected system crashes and reboots, disrupting critical services, especially in environments relying on Linux servers for networking, cloud infrastructure, or telecommunications. Organizations in sectors such as finance, healthcare, government, and telecommunications could experience operational interruptions, data unavailability, and potential cascading effects on dependent systems. Since the vulnerability is triggered by hardware bugs or out-of-order RX buffers, it may be exploited indirectly by sending malformed or high-volume network traffic to affected systems, causing instability. Although it does not directly compromise confidentiality or integrity, the availability impact can be significant in high-availability or real-time systems. The lack of known exploits reduces immediate risk, but unpatched systems remain vulnerable to accidental or deliberate triggering of the bug. European data centers and cloud providers using affected Linux kernels with Broadcom NICs could face service degradation or outages, impacting end-users and business continuity.

1. Apply the official Linux kernel patches that fix the RX consumer index logic in the bnxt driver as soon as they are available and tested. 2. Identify and inventory all Linux systems using Broadcom NetXtreme network interface cards (NICs) and verify kernel versions against the affected commits. 3. Where patching is not immediately possible, consider temporarily disabling or replacing affected network interfaces to prevent triggering the bug. 4. Monitor system logs for kernel panics or oops related to bnxt_rx_pkt and RX ring resets to detect attempts to trigger the vulnerability. 5. Implement network-level protections such as rate limiting, anomaly detection, and filtering to reduce malformed or suspicious traffic that could provoke hardware bugs. 6. Coordinate with hardware vendors for firmware updates or NIC driver updates that may mitigate hardware-related RX buffer issues. 7. For critical infrastructure, deploy redundant network paths and failover mechanisms to maintain availability during potential crashes. 8. Maintain up-to-date backups and disaster recovery plans to minimize downtime impact. 9. Engage in proactive vulnerability management and testing to identify similar driver-level issues in other hardware components.