Incorrect authorization in Linux kernel - CVE-2026-89839

Vulnerability identifier: #VU150451

CSH Severity: Low

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

CVE-ID: CVE-2026-89839

CWE-ID: CWE-863

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to modify the system.advise extended attribute without proper authorization.

The vulnerability exists due to improper authorization in f2fs_xattr_advise_set() when setting the system.advise extended attribute through an idmapped f2fs mount. A local user can attempt to set the system.advise extended attribute to modify the system.advise extended attribute without proper authorization.

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/3b681229e9f8fb1dd29bc65983bf3c87779e4ca3
• https://git.kernel.org/stable/c/4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1
• https://git.kernel.org/stable/c/a54ffce4637acb0db8e695188a6c7f99f14c3576
• https://git.kernel.org/stable/c/ab31e3b774f5d06b4489cef6c297b48c47c9dcbd
• https://git.kernel.org/stable/c/c3e2692c7a58e0bdb84bd658d827e89dcecea3ad

• Incorrect authorization in Linux kernel f2fs
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more