CVE-2026-99054 is a vulnerability in Linux Kernel
Published on October 23, 2026
tipc: destroy topsrv workqueues before closing connections
In the Linux kernel, the following vulnerability has been resolved:
tipc: destroy topsrv workqueues before closing connections
tipc_topsrv_stop() closed subscriber connections while the topology
server's send and receive workqueues were still running. Socket
callbacks and subscription events could then queue more work, and
in-flight send/recv work could drop the last connection reference
during the conn_idr walk.
That race produced several teardown failures: refcount_t addition on
0 from conn_get() on a connection whose release was blocked on
idr_lock, a subsequent use-after-free in tipc_conn_close(),
queue_work() on an already destroyed workqueue from the listener
data-ready callback, and an RCU stall in tipc_topsrv_exit_net()
while the walk spun under idr_lock.
Clear srv->listener under idr_lock so it acts as a shutdown flag,
skip queue_work() once it is NULL, destroy the workqueues to flush
in-flight work, and only then close the remaining connections.
Refuse tipc_conn_lookup() after that flag is cleared, and drop
idr_lock when the teardown walk finds no connection, so an
in-flight subscription event cannot pin idr_in_use while the
walk holds the lock.
v3 supersedes the narrower in-thread diff Tung Quang Nguyen
posted on 2026-09-23. It keeps his teardown order and adds the
lookup refusal and the empty-idr unlock.
Products Associated with CVE-2026-99054
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Affected Versions
Linux:- Version c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and below 7f796bb3b440d7f1b14c0e3b520462eb34f553af is affected.
- Version c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and below da9c16568bc79140a54c1f5fcf07a0305df47b37 is affected.
- Version c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and below 0af8780bdfdfc91fb9127bddb9c48fab67dc9d9e is affected.
- Version c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and below fb717c536af2aafeca520ff11d1e0f25f7ab8fa9 is affected.
- Version c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f and below 3acdd44385bc7e2e57605e073691ce69cc5a960d is affected.
- Version 3.11 is affected.
- Before 3.11 is unaffected.
- Version 6.6.160, <= 6.6.* is unaffected.
- Version 6.12.113, <= 6.12.* is unaffected.
- Version 6.18.57, <= 6.18.* is unaffected.
- Version 7.2.11, <= 7.2.* is unaffected.
- Version 7.3, <= * is unaffected.