Linux kernel i40e: missing bound check on VF-supplied action_meta allows out-of-bounds dereference

CVSS 8.8CVE-2025-39970Kernel, userspace & hypervisorcurated

Impact

The i40e PF driver accepted an action_meta index from a virtual function with an off-by-one comparison, so a malicious or buggy VF can drive an out-of-bounds dereference in the host PF driver. The CVSS vector marks the scope as changed, which is the usual signal for a guest-to-host crossing on SR-IOV: the attacker runs inside a VM or container that owns an i40e VF and reaches host kernel memory. On a GPU node that uses SR-IOV to hand tenants a slice of an Intel X710/XL710 NIC, that is a tenant-reachable path into the host. Worst case is a host kernel crash that takes every co-tenant job on the node with it.

Who can reach it

Local to the guest: any tenant that controls a VF of an i40e NIC and can send the virtchnl config messages the PF trusts. No host credentials needed; no network-only path.

What to do

Pick up the fixed stable kernel (the five linked stable commits cover the maintained branches) and reboot the node. There is no runtime toggle, so the only cheaper mitigation is to stop handing i40e VFs to untrusted tenants until the node is rebooted on a patched kernel. Drain the node first, since a reboot ends all resident GPU jobs.

References

https://nvd.nist.gov/vuln/detail/CVE-2025-39970 https://git.kernel.org/stable/c/28465770ca3b694286ff9ed6dfd558413f57d98f https://git.kernel.org/stable/c/3118f41d8fa57b005f53ec3db2ba5eab1d7ba12b https://git.kernel.org/stable/c/3883e9702b6a4945e93b16c070f338a9f5b496f9

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.