A fault in the Linux kernel atl1c driver causes an out‑of‑range tpd_cons value to trigger an infinite loop during TX ring cleanup, resulting in a kernel soft lockup. The affected CPU stalls for extended periods, effectively rendering the affected system unresponsive or severely degraded. This condition can be exploited by an attacker who can induce a link reset on the network interface, allowing a denial‑of‑service attack but does not compromise confidentiality or integrity.

The vulnerability affects all Linux kernel versions deployed on systems using the Qualcomm Atheros AR8151 v2.0 network interface, notably Ubuntu 26.04.1 LTS kernel 7.0.0‑31‑generic and Proxmox VE 7.0.14‑11‑pve with kernel 7.0.14‑11‑pve. The issue is tied to environments where an upstream PCIe link to the NIC can be reset, for example by a Mikrotik CCR2004 card.

With an absence of an available public exploit, the primary risk is the potential for a corruption of the kernel loop by an out‑of‑range read, which leads to a medium‑severity denial of service. The exploit vector is inferred to be a local or physical one, requiring the attacker to trigger a link reset that causes the destructive read. The vulnerability’s CVSS score is 6.5 and its EPSS score is < 1%. The vulnerability is not currently listed in KEV, but the impact level warrants attention.