Use-after-free in Linux kernel - CVE-2026-90256

Vulnerability identifier: #VU151234

CSH Severity: Medium

CVSS v4: 6 [CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-90256

CWE-ID: CWE-416

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to use-after-free in the Bluetooth L2CAP l2cap_disconn_ind function when processing concurrent L2CAP connection deletion. A remote attacker can trigger concurrent L2CAP disconnection processing to cause a denial of service.

Linux kernel
Debian Linux
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)
linux (Debian 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
linux (Debian package) - update to 6.12.115-2

• https://git.kernel.org/stable/c/2b66c83ff1751d6bd3201b3017206262ab46dc05
• https://git.kernel.org/stable/c/b495a3a9b33bc4e4613e685bf5c96c136caa22d8

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