CVE-2025-40108 serial: qcom-geni: Fix blocked task
A regression in the Qualcomm GENI serial driver causes system hangs during boot, resulting in a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40108?
CVE-2025-40108 is a denial of service vulnerability in Linux, published on 9 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
serial: qcom-geni: Fix blocked task
Revert commit 1afa70632c39 ("serial: qcom-geni: Enable PM runtime for serial driver") and its dependent commit 86fa39dd6fb7 ("serial: qcom-geni: Enable Serial on SA8255p Qualcomm platforms") because the first one causes regression - hang task on Qualcomm RB1 board (QRB2210) and unable to use serial at all during normal boot:
INFO: task kworker/u16:0:12 blocked for more than 42 seconds. Not tainted 6.17.0-rc1-00004-g53e760d89498 #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:0 state:D stack:0 pid:12 tgid:12 ppid:2 task_flags:0x4208060 flags:0x00000010 Workqueue: async async_run_entry_fn Call trace: __switch_to+0xe8/0x1a0 (T) __schedule+0x290/0x7c0 schedule+0x34/0x118 rpm_resume+0x14c/0x66c rpm_resume+0x2a4/0x66c rpm_resume+0x2a4/0x66c rpm_resume+0x2a4/0x66c __pm_runtime_resume+0x50/0x9c __driver_probe_device+0x58/0x120 driver_probe_device+0x3c/0x154 __driver_attach_async_helper+0x4c/0xc0 async_run_entry_fn+0x34/0xe0 process_one_work+0x148/0x290 worker_thread+0x2c4/0x3e0 kthread+0x118/0x1c0 ret_from_fork+0x10/0x20
The issue was reported on 12th of August and was ignored by author of commits introducing issue for two weeks. Only after complaining author produced a fix which did not work, so if original commits cannot be reliably fixed for 5 weeks, they obviously are buggy and need to be dropped.
Which versions are affected by CVE-2025-40108?
How do I fix CVE-2025-40108?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-40108 being exploited?
There is no known exploitation of CVE-2025-40108 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40108, GHSA-wqc8-4945-8xxr, UBUNTU-CVE-2025-40108.