SB20261022147 - Out-of-bounds write in Linux kernel net

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-98570)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service by triggering kernel memory corruption.

The vulnerability exists due to insufficient MAC-header headroom allocation in dst_dev_overhead() when IPv6 lightweight tunnels rebuild headers for packets whose MAC header exceeds the egress device's reserved space. A remote attacker can send IPv6 traffic through an affected forwarding path to trigger an out-of-bounds write in kernel memory and potentially crash the system.

An affected ingress configuration is a VLAN device with reorder_hdr disabled.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/36c07127924f11fc5741a780abcaaf808fe9ef13
• https://git.kernel.org/stable/c/87cd6b717e4069dca34e0866e57eaeb44d3b173e