CVE-2026-90393

/// Technical description

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

bpf: Fix potential UAF in bpf_netns_link_update_prog

In bpf_netns_link_update_prog, the checks for old_prog and prog type

are currently performed locklessly before acquiring netns_bpf_mutex.

This creates a race condition that can lead to a UAF issue.

If two threads concurrently execute BPF_LINK_UPDATE on the same netns

link, the following execution path can trigger a UAF:

CPU0 CPU1

bpf_netns_link_update_prog

if (old_prog && old_prog != link->prog)

return -EPERM;

bpf_netns_link_update_prog

if (old_prog && old_prog != link->prog)

...

old_prog = xchg(&link->prog, new_prog);

bpf_prog_put(old_prog);

if (new_prog->type != link->prog->type)

/// 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