Use-after-free in Linux kernel - CVE-2026-98491

Vulnerability identifier: #VU156791

CSH Severity: Medium

CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98491

CWE-ID: CWE-416

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to potentially cause a denial of service through kernel memory corruption.

The vulnerability exists due to use-after-free in the Linux kernel Open vSwitch connection-tracking component when cloned packets sharing an unconfirmed connection-tracking entry are committed with different extension sets. A remote attacker can trigger packet processing through the affected commit sequence to invalidate an extension pointer in the expectation list, potentially causing a kernel crash when the entry is later destroyed.

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/26b2bd70d22457556e2fa01cbf1192cb1a94d619
• https://git.kernel.org/stable/c/37e3c878b183a115f9a114067f9ef3b408ad27fb
• https://git.kernel.org/stable/c/457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55
• https://git.kernel.org/stable/c/55e5256adf3940e71802e2f749cacf81518726b0
• https://git.kernel.org/stable/c/707c2dc77891a874f4e8c52c285a511079164ec8
• https://git.kernel.org/stable/c/de41ee24f77b0fc45397db3e277cae2adbd43dfe
• https://git.kernel.org/stable/c/e0fa5ea434b7e8467ef3adc64e3858b1ca2a642d
• https://git.kernel.org/stable/c/e2829ae5459ddb5fce526b2e84697edf6c0c3cef

• Use-after-free in Linux kernel openvswitch
• 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