SB20260912298 - Improper control of a resource through its lifetime in Linux kernel openvswitch

Description

This security bulletin contains information about 1 vulnerability.

1) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-89487)

CWE-ID: CWE-664 - Improper control of a resource through its lifetime

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to modify page-cache data.

The vulnerability exists due to improper handling of zero-copy packet buffer flags in the Open vSwitch datapath when a failed USERSPACE upcall is followed by local ESP-in-UDP delivery. A local user can trigger a failed USERSPACE upcall followed by local ESP-in-UDP delivery to modify page-cache data.

Exploitation requires a MSG_ZEROCOPY packet carrying page-cache fragments.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0dbc2398fca3bb33eda963849f865ddb1b3aa05e
• https://git.kernel.org/stable/c/5d85eef222cfd28e73deed7402c100229e8b9e6e
• https://git.kernel.org/stable/c/6767d70cf46f65807a6a4c4406a518e6c12e36ae
• https://git.kernel.org/stable/c/e41a59fc056f63a7a1f42788913c53cc48d744aa