CVE-2026-23359

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf: Fix stack-out-of-bounds write in devmap<br /> <br /> get_upper_ifindexes() iterates over all upper devices and writes their<br /> indices into an array without checking bounds.<br /> <br /> Also the callers assume that the max number of upper devices is<br /> MAX_NEST_DEV and allocate excluded_devices[1+MAX_NEST_DEV] on the stack,<br /> but that assumption is not correct and the number of upper devices could<br /> be larger than MAX_NEST_DEV (e.g., many macvlans), causing a<br /> stack-out-of-bounds write.<br /> <br /> Add a max parameter to get_upper_ifindexes() to avoid the issue.<br /> When there are too many upper devices, return -EOVERFLOW and abort the<br /> redirect.<br /> <br /> To reproduce, create more than MAX_NEST_DEV(8) macvlans on a device with<br /> an XDP program attached using BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS.<br /> Then send a packet to the device to trigger the XDP redirect path.