Reachable assertion in Linux kernel - CVE-2026-98278

Vulnerability identifier: #VU153746

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98278

CWE-ID: CWE-617

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to trigger a kernel warning.

The vulnerability exists due to a reachable warning assertion in dev_fill_forward_path() when a flowtable attempts to offload a flow through a tunnel with a routing loop. A local privileged user can configure the route to the tunnel's remote endpoint to resolve back to the tunnel itself to trigger a kernel warning.

Exploitation requires the CAP_NET_ADMIN capability.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (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 (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
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/150dba2c69e93302af24a0c868eebe4871e2e107
• https://git.kernel.org/stable/c/d8eb177632dacda28bc6130c2105afbf5b791eb0

• Reachable assertion in Linux kernel core
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more