Incorrect authorization in Linux kernel - CVE-2026-90153

Vulnerability identifier: #VU151328

CSH Severity: High

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-90153

CWE-ID: CWE-863

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain unauthorized access.

The vulnerability exists due to improper authorization in smb_check_perm_dacl() in the ksmbd SMB server when processing a crafted DACL during SMB2_CREATE access validation. A remote attacker can submit a crafted DACL containing an access-granting ACE beyond its declared boundary to gain unauthorized access.

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/79decd88dd3f0d42e7fb0689b1a7853bfa302459
• https://git.kernel.org/stable/c/8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67
• https://git.kernel.org/stable/c/a2051ffe452afad52f580b85a3fd8851933b1e7c
• https://git.kernel.org/stable/c/a29f57a14c939586d84d7fd6a029bd1fd170098f
• https://git.kernel.org/stable/c/a4a307d149327dad5fb25187e1b03cebd1b04de6

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