CVE-2026-97481 serial: 8250: fix possible ISR soft lockup
A missing FIFO error IRQ handling in the Linux kernel 8250 serial driver can cause a soft lockup during startup, leading to 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-2026-97481?
CVE-2026-97481 is a denial of service vulnerability in Linux, published on 24 Sep 2026. 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: 8250: fix possible ISR soft lockup
There are rare cases in which the host gets stuck in the ISR because it is flooded with messages during the startup phase.
The reason for the soft lockup in the ISR is the missing FIFO error IRQ (FIFOE) handling. Not handling it and reporting IRQ_HANDLED triggers the IRQ immediately again.
Fix this by adding a check for the FIFOE status and clearing the FIFO if no data is ready (DR).
This behavior was observed on an AM62L device which uses the OMAP 8250 driver. Fix it for all 8250 drivers, since the OMAP driver's special IRQ setup handling may trigger this behavior more frequently, but it is not ensured that other 8250 drivers aren't affected.
Which versions are affected by CVE-2026-97481?
How do I fix CVE-2026-97481?
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-2026-97481 being exploited?
There is no known exploitation of CVE-2026-97481 in the wild and no public exploit code.
Sources
Also known as AZL-104010, BELL-CVE-2026-97481, DEBIAN-CVE-2026-97481, GHSA-whv8-h8xw-cr4q, UBUNTU-CVE-2026-97481.