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VulnerabilityPublished Updated

CVE-2025-21827: Linux kernel · Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()

Source GCVE Database

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Not known to be exploited · CVSS 5.5 Medium.

Data as of 29 Oct 2026, 23:32 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

AI-suggested

A fix has been implemented in the Linux kernel to add the required locking around usb_driver_claim_interface() in the Mediatek btusb driver. Users should update to the fixed kernel version once available. No additional mitigation steps are indicated.

Description

CVE-2025-21827 is a medium severity vulnerability in the Linux kernel's Bluetooth Mediatek btusb driver. It involves missing locks around the usb_driver_claim_interface() function when called outside of probe(), leading to potential errors such as failure to claim the ISO interface or NULL pointer dereferences. The issue arises because the device lock was not held during certain operations, causing race conditions and instability. The vulnerability has been resolved by adding the appropriate locking to ensure safe access.

References

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