Improper update of reference count in Linux kernel - CVE-2026-89885

Vulnerability identifier: #VU150408

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-89885

CWE-ID: CWE-911

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to compromise confidentiality, integrity, and availability.

The vulnerability exists due to improper reference count handling in the mtk-mdp3 mdp_probe() fallback SCP device lookup when the SCP handle lookup fails. A remote attacker can trigger the MDP device probe to compromise confidentiality, integrity, and availability.

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 6.12.111-1

• https://git.kernel.org/stable/c/0259ade4c4ceaf1e184a7c1aea8071ad398f9b6f
• https://git.kernel.org/stable/c/252850653569fdb1a259937e02325cf32c8f0970
• https://git.kernel.org/stable/c/55793e4665b7f15151e6f5ab51ca980e73abed5d
• https://git.kernel.org/stable/c/dce13bd9bade3ecc1acb7579397f24743850997f

• Improper update of reference count in Linux kernel mediatek mdp3 driver
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more