# CVE-2026-10663: Use-after-free / double-free of the root USB device in the experimental USB host stack

> A physical attacker can trigger a use-after-free and double-free in Zephyr's experimental USB host stack, causing crashes or memory corruption.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jul 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-26q8-xjq3-f5p6

## What is CVE-2026-10663?

CVE-2026-10663 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 12 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Zephyr's experimental USB host stack (CONFIG_USB_HOST_STACK), usbh_device_disconnect() (subsys/usb/host/usbh_device.c) freed the root usb_device slab object without clearing the cached pointer ctx->root. The bus removal handler dev_removed_handler() (subsys/usb/host/usbh_core.c) decides what to tear down solely from ctx->root, checking only that it is non-NULL.

Because UHC controller drivers (e.g. uhc_max3421e, uhc_mcux_common) synthesize UHC_EVT_DEV_REMOVED directly from physical bus line state with no debounce or state guard, an attacker with physical USB access (or a rogue device that bounces its connection) can deliver a second device-removed event after a root device disconnect. The handler then re-enters usbh_device_disconnect() with the dangling pointer, locking a mutex inside the freed object (use-after-free), removing the freed node from the device list, and calling k_mem_slab_free() on the already-freed block (double-free). If the slab block has been reissued to a newly attached device in between, this corrupts a live object.

Impact is denial of service (crash) and memory corruption; the attack vector is physical/local. The flaw was introduced in v4.4.0 by the connect/disconnect refactor and is fixed by clearing ctx->root in usbh_device_disconnect() before freeing.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-10663?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-10663?

No fix has been published for CVE-2026-10663 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10663 being exploited?

There is no known exploitation of CVE-2026-10663 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-10663 and fix it if it is affected.

What it is: CVE-2026-10663 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 12 Jul 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-2026-10663 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. 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-2026-10663/ (Markdown: https://insights.sbomify.com/CVE-2026-10663/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10663
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10663
- OSV: https://osv.dev/vulnerability/CVE-2026-10663

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10663/
Summaries are generated and may contain mistakes; the official description above is the record.