CVE-2026-53089

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References