Use-after-free in Linux kernel - CVE-2026-98559

Vulnerability identifier: #VU156863

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-2026-98559

CWE-ID: CWE-416

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to potentially cause a denial of service through invalid kernel memory access.

The vulnerability exists due to use-after-free in the Linux kernel SMC function smcr_port_err() when traversing smc_lgr_list.list without holding smc_lgr_list.lock. A local user can potentially trigger a race between this traversal and concurrent smc_lgr_terminate_sched() execution to cause a denial of service by dereferencing a freed link group.

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/00a59600ae72d24859d0ad1783a78bc921bc2599
• https://git.kernel.org/stable/c/0edcc4284392b28826b5d37532b366b291e6e0fa
• https://git.kernel.org/stable/c/34bcf11cd2528ae00bb6d764d808083c66824277
• https://git.kernel.org/stable/c/3d35f069e1c119992000d51236dbe54da2d4e61e
• https://git.kernel.org/stable/c/3d65a2eb4449fc9658fb860dea893025d028d90e
• https://git.kernel.org/stable/c/61cb282fe97b3b0ba32ca09417a693162bf4ae3f
• https://git.kernel.org/stable/c/a9b968e42690d784c241a0761c10253271f7df5d

• Use-after-free in Linux kernel smc
• 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