CVE-2026-80998
Received Received - Intake

TX Queue Stall in Linux Kernel bnxt Driver

Vulnerability report for CVE-2026-80998, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: bnxt: ring the doorbell when SW USO exits early When a burst of packets is handed down to the driver, the driver defers the doorbell to the end by setting txr->kick_pending = 1. The normal TX path handles this, but the SW USO path can miss it if it returns early. If bnxt_sw_udp_gso_xmit runs but returns early with NETDEV_TX_BUSY and txr->kick_pending was previously set to 1, then the TX queue can stall because the driver wrote some BDs but never wrote the doorbell. The device won't know to do the TX which would generate the completion that would wake the queue back up. Simplify bnxt_sw_udp_gso_xmit to set txr->kick_pending in its success case and check the flag on return. The added check after bnxt_sw_udp_gso_xmit returns ensures that any pending doorbells are written handling both successful USO and any early returns, which prevents the TX queue stall mentioned above. This TX queue stall was observed on a production system with a netdev TX watchdog informing about the queue stall.

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Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-12
AI Q&A
2026-09-12
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a TX queue stall in the Broadcom NetXtreme-C/E network driver (bnxt). When handling a burst of packets, the driver defers ringing the doorbell to signal the hardware to transmit. The SW USO path can miss this if it exits early, leaving the doorbell unset. If bnxt_sw_udp_gso_xmit returns early with NETDEV_TX_BUSY while a doorbell is pending, the TX queue stalls because the hardware never receives the transmit signal, halting further packet processing.

Detection Guidance

This vulnerability may cause a TX queue stall in the Linux kernel's bnxt driver. Detection involves monitoring for TX queue stalls or watchdog alerts. Check kernel logs for messages like 'netdev TX watchdog' or 'queue stall' using commands like 'dmesg | grep -i stall' or 'journalctl -k | grep -i stall'.

Impact Analysis

This vulnerability can cause network performance issues or complete loss of network connectivity on systems using affected Broadcom network hardware. It may lead to packet drops, increased latency, or system unresponsiveness due to stalled TX queues. Production systems relying on these network interfaces could experience service disruptions or failures.

Mitigation Strategies

Apply the Linux kernel patch that resolves this issue. Update to a kernel version containing the fix for CVE-2026-80998. If immediate patching is not possible, monitor network performance and restart affected services if queue stalls are detected.

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