Out-of-bounds read in Linux kernel - CVE-2026-63857

Vulnerability identifier: #VU138798

CSH Severity: Low

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

CVE-ID: CVE-2026-63857

CWE-ID: CWE-125

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 an out-of-bounds read in airoha_dev_xmit() when processing fragmented socket buffers. A local user can trigger transmission of a crafted fragmented packet to cause a denial of service.

The unsafe read occurs during the final loop iteration when the loop index reaches the fragment count, which may trigger a page fault.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/bde34e84edc8b5571fbde7e941e175a4293ee1eb
• https://git.kernel.org/stable/c/d78c8ab7bd84952e053d0c622b7fc1b4ad8a19a3
• https://git.kernel.org/stable/c/f670fa4b19ceddc6d215dda4997888ccba9bbc61

• Out-of-bounds read in Linux kernel ethernet airoha driver
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia