# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-104010, BELL-CVE-2026-97481, DEBIAN-CVE-2026-97481, GHSA-whv8-h8xw-cr4q, UBUNTU-CVE-2026-97481

## 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.

## Is CVE-2026-97481 being exploited?

There is no known exploitation of CVE-2026-97481 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97481 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-97481 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-97481/ (Markdown: https://insights.sbomify.com/CVE-2026-97481/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97481
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97481
- OSV: https://osv.dev/vulnerability/CVE-2026-97481

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97481/
Summaries are generated and may contain mistakes; the official description above is the record.