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VulnerabilityPublished Updated

CVE-2025-21859: Linux kernel · USB: gadget: f_midi: f_midi_complete to call queue_work

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1146.156~18.04.1 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 12:58 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.4.0-1146.156~18.04.1, 5.4.0-1151.158~18.04.1, 5.4.0-1149.158~18.04.1 +83
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 12 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-78.78
Fixed in
  • 6.8.0-78.78
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1035.37
Fixed in
  • 6.8.0-1035.37
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1034.39
Fixed in
  • 6.8.0-1034.39
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-1015.15~24.04.1
Fixed in
  • 6.11.0-1015.15~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1022.23
Fixed in
  • 6.8.0-1022.23
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1036.38
Fixed in
  • 6.8.0-1036.38

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and included in Linux kernel versions 5.4.0-1146.156 and later, as well as other fixed versions listed in the advisory. Users should update their Linux kernel to one of the fixed versions to remediate this issue. After updating, a system reboot is required to apply the fix. There are no additional mitigations required beyond applying the official kernel updates.

Description

A deadlock vulnerability exists in the Linux kernel's USB MIDI gadget driver (f_midi) due to a re-entrant lock acquisition in the f_midi_transmit function. This issue has been fixed by changing the completion handler to schedule the inner transmit call via a high priority work queue using queue_work(). The vulnerability affects multiple Linux kernel versions prior to 5.4.0-1146.156 and several older 3.x versions. The fix is included in Linux kernel versions 5.4.0-1146.156 and later. The vulnerability has a medium severity with a CVSS score of 5.5 and does not impact confidentiality or integrity but causes availability impact due to deadlock.

References

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