NULL pointer dereference in Linux kernel - CVE-2026-64404

Vulnerability identifier: #VU139556

CSH Severity: Low

CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64404

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a NULL pointer dereference in iso_conn_big_sync() when handling recvmsg on a PA-sync broadcast sink socket during connection teardown. A local user can trigger a race condition to cause a denial of service.

The issue is reachable from iso_sock_recvmsg() for a PA-sync broadcast sink socket with BT_SK_DEFER_SETUP and BT_SK_PA_SYNC set.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/01afd198c2c286cd3b81f44d4e33a2e638711550
• https://git.kernel.org/stable/c/b3e647a4aa4d2d054f86a783f5c426035e1dc237
• https://git.kernel.org/stable/c/b84eeb7636d6962dd882d5e0b31475e4f404313c
• https://git.kernel.org/stable/c/d5541eb148da72d5e0a1bca8ecd171f9fc8b366f

• NULL pointer dereference in Linux kernel bluetooth
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0