Race condition in Linux kernel - CVE-2026-63871

Vulnerability identifier: #VU138780

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-63871

CWE-ID: CWE-362

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 race condition in Bluetooth ISO socket handling in net/bluetooth/iso.c when calling hci_get_route() on iso_pi socket fields without holding the socket lock. A local user can trigger concurrent connect() or setsockopt() operations on the same socket to cause a denial of service.

The issue was reported by KCSAN as a data race during Bluetooth ISO connection and listening operations.

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/859bb1f4cb615d98c9c1ab2bd76ebb0b8fe46020
• https://git.kernel.org/stable/c/9798f7d41d85ff763afd1f1cc0533b5c416c8348
• https://git.kernel.org/stable/c/9ca7053d6215d89c33f28893bfd1625a32919d3f
• https://git.kernel.org/stable/c/ab84fd7779a2a7ff5d2c8eac212c43733f56216e

• Race condition 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