CVE-2026-80866

/// Technical description

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

tipc: avoid busy looping in tipc_exit_net()

Blamed commit introduced a busy-wait loop in tipc_exit_net()

to wait for pending UDP bearer cleanup works to complete:

while (atomic_read(&tn->wq_count))

cond_resched();

This loop can busy-wait for a long time if cond_resched() is a NOP. This

typically happens if the netns exit is executed by a high priority task,

or under kernels configured without preemption (CONFIG_PREEMPT_NONE). In

such cases, it wastes CPU cycles and can lead to soft lockups.

Fix this by replacing the busy loop with wait_var_event(), allowing the

thread to sleep properly until the work queue count reaches zero.

Accordingly, update cleanup_bearer() to use atomic_dec_and_test() and

wake_up_var() to wake up the waiter when the count drops to zero.

This uses the global wait queue hash table, avoiding the need to bloat

struct tipc_net with a wait_queue_head_t. The atomic_dec_and_t

/// 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