Improper update of reference count in Linux kernel - CVE-2026-98459

Vulnerability identifier: #VU156757

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98459

CWE-ID: CWE-911

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to potentially cause a denial of service by prematurely disconnecting a Bluetooth connection that is still in use.

The vulnerability exists due to improper reference counting in the Linux kernel Bluetooth ISO hci_bind_bis() function when linking an additional broadcast isochronous stream to an existing parent connection. A local user can trigger linking and subsequent unlinking of the child connection to drop the parent's existing operational hold, potentially scheduling the parent for disconnection while its socket is still using it.

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 kernel - update to 7.0 rc3
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/03a91cdf6862fb351a74f035ad21e70112438552
• https://git.kernel.org/stable/c/4c94557dd02569efa6c1072a0439addaef9a5224
• https://git.kernel.org/stable/c/4e49206d9574a4c109480198e73aea34ad0ed7f6
• https://git.kernel.org/stable/c/bbcd723ee7a84bc868142fd57717af88e54e555a
• https://git.kernel.org/stable/c/ff28e6c67143c76ef50c3eac01f2fad411705f71

• Improper update of reference count in Linux kernel bluetooth
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more