Use-after-free in Linux kernel - CVE-2026-90278

Vulnerability identifier: #VU151204

CSH Severity: Low

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

CVE-ID: CVE-2026-90278

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to trigger use-after-free access to llbitmap storage.

The vulnerability exists due to incorrect teardown ordering in the md bitmap teardown path when stopping an md device configured with llbitmap while RAID1 behind-write completions are pending. A local user can stop an affected md device while RAID1 behind-write completions are pending to trigger use-after-free access to llbitmap storage.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
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

• https://git.kernel.org/stable/c/2a79365b2278f16e163e4024086105693b421601
• https://git.kernel.org/stable/c/4224dccd325a9380e8edfb66aad8bb5771c94222
• https://git.kernel.org/stable/c/73881ff7a75913f919a1ce9d9571bfaab8e8588d

• Use-after-free in Linux kernel md driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more