CVE-2026-80866: Linux Vulnerability

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_test() provides the necessary memory barrier to ensure the wakeup is not missed.

Metrics

EPSS Probability

0.21%

11.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < 772769859226a5b004442403510acb58a1c32e72; >= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < 99b82c8452887408ea908fdfa5df33c4a5dfa88f; >= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < 110bb16d37bdba03213156c0df37e7119c190936; >= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < 7672973957e3e20780afe5937a9fec70b72bc060; >= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < 522d1d950b9e3b68190a6de7534827c8dccedb73; >= 04c26faa51d1e2fe71cf13c45791f5174c37f986, < c1481c94e74c955e0448ddf46b8615a44d840c1e; d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa; 5195ec5e365a2a9331bfeb585b613a6e94f98dba; b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d; >= 5.4.124, < 5.5; >= 5.10.42, < 5.11; >= 5.12.9, < 5.13
Linux	Linux	5.13

References

Timeline

Published: Sep 4, 2026
Last Modified: Oct 30, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-80866?

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_test() provides the necessary memory barrier to ensure the wakeup is not missed.

How severe is CVE-2026-80866?

Severity scoring for CVE-2026-80866 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-80866?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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