Improper initialization in Linux kernel - CVE-2026-90021

Vulnerability identifier: #VU150258

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-90021

CWE-ID: CWE-665

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a kernel warning.

The vulnerability exists due to improper initialization of a work structure in f_midi_alloc() when freeing a MIDI gadget function that was not bound. A local user can free an unbound MIDI gadget function to cause a kernel warning.

The warning occurs in __flush_work because the work function pointer is null.

Linux kernel
Debian Linux
SUSE Linux Micro Extras
SUSE Linux Micro
Ubuntu
linux (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
kernel-64kb
kernel-default-devel-debuginfo
kernel-default-debugsource
kernel-obs-build-debugsource
kernel-obs-build
kernel-syms
kernel-default-devel
kernel-64kb-devel
kernel-64kb-debugsource
kernel-default
linux (Debian package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17
kernel-64kb - update to 6.4.0-159998.55.1
kernel-default-devel-debuginfo - update to 6.4.0-159998.55.1
kernel-default-debugsource - update to 6.4.0-159998.55.1
kernel-obs-build-debugsource - update to 6.4.0-159998.55.1
kernel-obs-build - update to 6.4.0-159998.55.1
kernel-syms - update to 6.4.0-159998.55.1
kernel-default-devel - update to 6.4.0-159998.55.1
kernel-64kb-devel - update to 6.4.0-159998.55.1
kernel-64kb-debugsource - update to 6.4.0-159998.55.1
kernel-default - update to 6.4.0-159998.55.1
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/02ac76f27db23ef652358458c272d9d2d6f51167
• https://git.kernel.org/stable/c/3d8b11255e632170f32f1925bfcaf96331f36317
• https://git.kernel.org/stable/c/7e07d3e4c389217d7d7171d80edf2e23ac70f1ea
• https://git.kernel.org/stable/c/858576de6b2f5166b08dae803f0fd0766dcb3002

• Improper initialization in Linux kernel gadget function driver
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• SUSE update for the Linux Kernel