# CVE-2026-10663 — zephyrproject zephyr

> As of 2026-07-13, CVE-2026-10663 is a MEDIUM-severity vulnerability in zephyrproject zephyr, CVSS v3.1 6.1, EPSS 0.1% (5.4th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-10663 as of 2026-07-13; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-07-13

## What is CVE-2026-10663?

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.

The record classifies CVE-2026-10663 under weakness class [CWE-416](https://intel.threadlinqs.com/cwe/CWE-416). Its CVSS v3 base vector states that the flaw requires physical access to the device, needs no prior authentication, needs no user interaction, and has high impact on integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 85 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 6.1 — MEDIUM (`CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 5.4% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-12, last modified 2026-07-13

## Is CVE-2026-10663 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [zephyrproject](https://intel.threadlinqs.com/vendors/zephyrproject): zephyr

## How to fix CVE-2026-10663

No vendor patch reference has been recorded for CVE-2026-10663 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-10663

No threat campaign in the Threadlinqs corpus currently references CVE-2026-10663, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-07-14. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/zephyrproject-rtos/zephyr/commit/4b87a8f161a44cb19505fa97db7cf72f64d49165)

**Other references**

- [github.com](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-26q8-xjq3-f5p6)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-10663
Full detection coverage and IOCs for threats exploiting CVE-2026-10663 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp