Out-of-bounds write in Linux kernel - CVE-2026-98588

Vulnerability identifier: #VU156891

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98588

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to corrupt kernel memory or cause a denial of service.

The vulnerability exists due to an out-of-bounds write in sock_map_free() when freeing a SOCKMAP whose entry count exceeds the range of its signed integer iterator. A local privileged user can create and destroy a SOCKMAP with max_entries = 0xffffffff to trigger signed integer overflow and write outside the socket array, corrupting an unrelated allocation or crashing the kernel.

Exploitation requires the 32 GiB allocation to succeed on a large-memory host.

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/814a81c842bd88f6bd8a4ce550d560df071a5d03
• https://git.kernel.org/stable/c/909f761868fda329dc69130ef9eb5b5795bcdf00
• https://git.kernel.org/stable/c/ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8
• https://git.kernel.org/stable/c/c56191af3a578b9cc265fa3bd5fc0752c59c1781
• https://git.kernel.org/stable/c/cc70972ddbf0e3398f2f32624d31db78594d50d8
• https://git.kernel.org/stable/c/cea597519b9ca6d691c98d92460ead8ece2a07af
• https://git.kernel.org/stable/c/f4a73f49e256bd835368504462be3b57b03febff

• Out-of-bounds write in Linux kernel core
• 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