Use-after-free in Linux kernel - CVE-2026-90303

Vulnerability identifier: #VU151186

CSH Severity: Low

CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-90303

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to use-after-free in show_pte() when handling user faults concurrently with munmap() calls. A local user can trigger a user fault while another thread in the same process calls munmap() to cause a denial of service.

Exploitation requires CONFIG_DEBUG_USER=y and the user_debug=31 command-line setting.

Linux kernel
Debian Linux
Ubuntu
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-azure-fde (Ubuntu package)
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)
linux (Debian package)

Install security update from vendor's repository.

linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1059.59
linux-nvidia-tegra (Ubuntu package) - update to 5.15.0-1070.72
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux-azure-fde (Ubuntu package) - update to 5.15.0-1124.133
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
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0
• https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66
• https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd
• https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba
• https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7
• https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545
• https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892
• https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549

• Use-after-free in Linux kernel arm mm
• Debian update for linux
• Ubuntu update for linux-azure-fde
• 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