Incorrect Calculation of Buffer Size in Linux kernel - CVE-2026-90366

Vulnerability identifier: #VU151122

CSH Severity: Low

CVSS v4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-90366

CWE-ID: CWE-131

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to cause a denial of service.

The vulnerability exists due to an incorrect buffer size calculation in the MT7996 beacon update size calculation when processing a beacon update while a CSA countdown is active. A local privileged user can trigger the emission of two bss_bcn_cntdwn_tlv entries to cause a denial of service.

Exploitation requires MBSSID to be enabled and a near-maximum beacon template.

Linux kernel
Debian Linux
SUSE Linux Micro Extras
SUSE Linux Micro
Ubuntu
linux (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
kernel-64kb
kernel-default-devel-debuginfo
kernel-default-debugsource
kernel-obs-build-debugsource
kernel-obs-build
kernel-syms
kernel-default-devel
kernel-64kb-devel
kernel-64kb-debugsource
kernel-default
linux (Debian package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
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
kernel-64kb - update to 6.4.0-159998.55.1
kernel-default-devel-debuginfo - update to 6.4.0-159998.55.1
kernel-default-debugsource - update to 6.4.0-159998.55.1
kernel-obs-build-debugsource - update to 6.4.0-159998.55.1
kernel-obs-build - update to 6.4.0-159998.55.1
kernel-syms - update to 6.4.0-159998.55.1
kernel-default-devel - update to 6.4.0-159998.55.1
kernel-64kb-devel - update to 6.4.0-159998.55.1
kernel-64kb-debugsource - update to 6.4.0-159998.55.1
kernel-default - update to 6.4.0-159998.55.1
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/1a51aff0e048dc5b8252d65808b79939c942d6ec
• https://git.kernel.org/stable/c/1d348f96623ec20d700af7d4dfc00a74da6238ac
• https://git.kernel.org/stable/c/45d8896e4cffffb2c6554ccbec6efe7a0d53166f
• https://git.kernel.org/stable/c/50c66bab321140c49aa2ed779a3ec9d2f085b458
• https://git.kernel.org/stable/c/bc1d694a1ffe0062c3adf0db1d64ad54454398ec

• Incorrect Calculation of Buffer Size in Linux kernel mt76 mt7996 driver
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• SUSE update for the Linux Kernel