CVE-2026-23359: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.1% chance of exploitation in the next 30 days.

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

Affected products

• Linux Linux Kernel: from 5.15.1, before 5.15.203 (fixed in 5.15.203); from 5.16, before 6.1.167 (fixed in 6.1.167); from 6.2, before 6.6.130 (fixed in 6.6.130); from 6.7, before 6.12.77 (fixed in 6.12.77); from 6.13, before 6.18.17 (fixed in 6.18.17); from 6.19, before 6.19.7 (fixed in 6.19.7); …

Published 2026-03-25. Last modified 2026-07-14.