In the Linux kernel, the following vulnerability has been resolved: net: atl1c: fix soft lockup on out-of-range tpd_cons read The hardware can… (CVE-2026-98489)

The Linux kernel atl1c network driver contained a defect where an out-of-range tpd_cons value (0xffff) reported by the hardware during PCIe link or MAC reset caused an infinite loop in the atl1c_clean_tx function. This loop resulted in a CPU soft lockup, as the driver continuously waited for a condition that could never be met. The issue was confirmed on multiple machines with Qualcomm Atheros AR8151 v2.0 NICs, triggered by rebooting a Mikrotik CCR2004 PCIe card. The fix involves treating the out-of-range tpd_cons value as "nothing new to clean" to avoid the infinite loop and subsequent soft lockup.

The vulnerability causes a CPU soft lockup on affected systems, leading to a stalled network transmit queue and potential system instability or degraded network performance. It affects systems using the atl1c driver with Qualcomm Atheros AR8151 v2.0 NICs under specific conditions such as PCIe link or MAC reset. No evidence of remote code execution or privilege escalation is indicated.

A fix has been implemented in the Linux kernel to handle the out-of-range tpd_cons value properly by treating it as "nothing new to clean" to prevent the infinite loop and soft lockup. Users should update their Linux kernel to a version that includes this fix. Since this is a kernel driver issue, applying the official kernel update is the recommended remediation.