CVE-2026-98382bpf: Reject dev-bound-only programs on other devices

Official description

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject dev-bound-only programs on other devices __bpf_offload_dev_match() falls back to comparing offdev pointers after an exact netdev mismatch. Bound-only programs normally have NULL offdevs, so unrelated netdevs compare equal. A bound-only program on an offload-registered netdev can instead inherit a real offdev and match a sibling port. With CAP_BPF and CAP_NET_ADMIN, a caller can use bpf(BPF_LINK_CREATE) with a different target ifindex to run metadata kfuncs specialized for the bound driver on the target driver's xdp_buff. Running a veth-bound program on tun reads beyond tun's bare stack xdp_buff as a veth_xdp_buff. Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:veth_xdp_rx_timestamp (drivers/net/veth.c:1673) Call Trace: ... tun_build_skb (drivers/net/tun.c:1739) tun_get_user (drivers/net/tun.c:1856) tun_chr_write_iter (drivers/net/tun.c:2091) vfs_write (fs/read_write.c:595 fs/read_write.c:687) ksys_write (fs/read_write.c:739) do_syscall_64 (arch/x86/entry/syscall_64.c:84) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Kernel panic - not syncing: Fatal exception in interrupt Restrict non-offloaded programs to exact netdev matches and retain the shared-offdev fallback only for genuinely offloaded multi-port programs.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e57f04194361574493e3e6cf0b9e9c69e4ae9791
• https://git.kernel.org/stable/c/0dceda331180617aeeb22381e8480b37f18ba08b
• https://git.kernel.org/stable/c/940b626854de200e6187777d42114727daca617c
• https://git.kernel.org/stable/c/bb375f3c5990e29851894f20ebc4b9dbc6676126
• https://git.kernel.org/stable/c/6db1ce73e9853f533eb7f413f14ba00f8ec6f80d