CVE-2026-53089

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix use-after-free in offloaded map/prog info fill

When querying info for an offloaded BPF map or program,

bpf_map_offload_info_fill_ns() and bpf_prog_offload_info_fill_ns()

obtain the network namespace with get_net(dev_net(offmap->netdev)).

However, the associated netdev's netns may be racing with teardown

during netns destruction. If the netns refcount has already reached 0,

get_net() performs a refcount_t increment on 0, triggering:

refcount_t: addition on 0; use-after-free.

Although rtnl_lock and bpf_devs_lock ensure the netdev pointer remains

valid, they cannot prevent the netns refcount from reaching zero.

Fix this by using maybe_get_net() instead of get_net(). maybe_get_net()

uses refcount_inc_not_zero() and returns NULL if the refcount is already

zero, which causes ns_get_path_cb() to fail and the caller to return

-ENOENT -- the correct behavior when the netns is being destroyed.