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 report an out-of-range tpd_cons (seen as 0xffff) while the PCIe link/MAC is resetting. An out-of-range value can never be reached and the loop below would spin forever. To avoid a soft lockup treat it as "nothing new to clean" instead. Reproduced on two machines, same NIC (Qualcomm Atheros AR8151 v2.0, 4-port), triggered by rebooting a Mikrotik CCR2004 PCIe card that the ports are directly linked to: - Ubuntu 26.04.1 LTS, kernel 7.0.0-31-generic. The link-flap precursor, before the lockup was captured with a full trace elsewhere: atl1c 0000:05:00.0 enp5s0f0: NETDEV WATCHDOG: CPU: 4: transmit queue 2 timed out 489984 ms atl1c 0000:05:00.0: MAC state machine can't be idle since disabled for 10ms second atl1c 0000:05:00.0: atl1c: enp5s0f0 NIC Link is Up<65535 Mbps Full Duplex> 65535 (0xffff) here is the same value tpd_cons reads back once the loop below gets stuck. - Proxmox VE, kernel 7.0.14-11-pve. Same NIC/trigger, this time caught by the soft lockup watchdog with a full stack trace: watchdog: BUG: soft lockup - CPU#12 stuck for 354s! [napi/eth%d-0:329] CPU: 12 UID: 0 PID: 329 Comm: napi/eth%d-0 Tainted: P O L 7.0.14-11-pve #1 PREEMPT(lazy) RIP: 0010:atl1c_clean_tx+0x142/0x2d0 [atl1c] Call Trace: <TASK> __napi_poll+0x32/0x1e0 napi_threaded_poll_loop+0x286/0x2e0 napi_threaded_poll+0xfd/0x140 kthread+0xf7/0x130 ret_from_fork+0x2da/0x3a0 ret_from_fork_asm+0x1a/0x30 </TASK>
Fix
Microsoft's update · Moderate
- Release Notes — azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 · build 6.6.159.1-1
From the 2026-Oct release note of Microsoft's Security Update Guide, revised 2026-10-28.
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 2
- StatusReceived → PublishedNVD modified 2026-10-19 09:20
- First seenunscoredNVD modified 2026-10-19 10:19
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 8
- https://git.kernel.org/stable/c/36c2009d90f2210ef92e6f4f2850e8b57b09e754
- https://git.kernel.org/stable/c/4daf80da0c38b8cd92c111ad96cb38322aabf586
- https://git.kernel.org/stable/c/57b55367b6e3accc55a989afeaf127063e3614dc
- https://git.kernel.org/stable/c/586847400b1168a88917287ac02c2c91a620b841
- https://git.kernel.org/stable/c/5ea2576a4f5ec476f33169fdbe9090d2b038ad13
- https://git.kernel.org/stable/c/9f2cc71a2e2799d9c993c73f1bd36507eef6ae43
- https://git.kernel.org/stable/c/d4ab263e40fcf7cfa38a43ec774067d32eb94e16
- https://git.kernel.org/stable/c/e7acd4cdeccbcdfd407adeb72b1eba14d1145b6f