Incorrect Bitwise Shift of Integer in Linux kernel - CVE-2026-98636

Vulnerability identifier: #VU156948

CSH Severity: Low

CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98636

CWE-ID: CWE-1335

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to trigger undefined kernel behavior that may cause a denial of service.

The vulnerability exists due to an incorrect bitwise shift in the squashfs_xz_comp_opts() function when processing a SquashFS image with the COMP_OPTS flag set to 1 and a dictionary size of zero. A local privileged user can cause a specially crafted image to be mounted to trigger a shift with an exponent of -1, resulting in undefined behavior that may cause a denial of service.

Linux kernel
Ubuntu
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws (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-nvidia-tegra (Ubuntu package) - update to 5.15.0-1070.72
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1059.59
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux (Ubuntu package) - update to 7.0.0-42.42
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
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/0cb85377daaefb4ce5ce72975f2deb27ee0e0cad
• https://git.kernel.org/stable/c/1f7745fb3580152ca902ef181b605f33cabfb1d0
• https://git.kernel.org/stable/c/7a1c293e7aa17f1afaee0684e0e931fe23a5a6b1
• https://git.kernel.org/stable/c/88c673a0bd233df44ca0020da82f4fd3876de27a
• https://git.kernel.org/stable/c/9d9c5c218ea356a1d88765214ad2919605280ab1
• https://git.kernel.org/stable/c/b02948a23455f8190a53887b2d2c13ae1d360cea
• https://git.kernel.org/stable/c/c68e0068a236f9a7dfc19720bdf11e5d80a85089
• https://git.kernel.org/stable/c/e1ca4e3a380ef3e8f46ce006f1146392e3f32c98

• Incorrect Bitwise Shift of Integer in Linux kernel squashfs
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• Ubuntu update for linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx
• Ubuntu update for linux, linux-aws, linux-aws-5.15 and more