In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Fix KASAN reported use-after-free when request is canceled
Alan reported that when doing stress testing sometimes KASAN notices
use-after-free during control channel operation (stripped down keeping
the relevant parts):
BUG: KASAN: slab-use-after-free in tb_cfg_request_sync+0x240/0x250 [thunderbolt]
Read of size 24 at addr ffff88811067f290 by task kworker/u40:2/1760
<TASK>
tb_cfg_request_sync+0x240/0x250 [thunderbolt]
tb_cfg_read_raw+0x367/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1760:
__kmalloc_cache_noprof+0x1ee/0x550
tb_cfg_read_raw+0x1d3/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
Freed by task 926:
kfree+0x18f/0x4a0
tb_cfg_request_put+0xb7/0xe0 [thunderbolt]
tb_cfg_request_work+0x82/0x120 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
Second to last potentially related work creation:
__queue_work+0x575/0xd00
queue_work_on+0x77/0x80
tb_cfg_request_cancel+0xc7/0x260 [thunderbolt]
tb_cfg_request_sync+0x1f6/0x250 [thunderbolt]
tb_cfg_read_raw+0x367/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
The last stack trace is helpful because it shows that we are cancelling
a request and looking at tb_cfg_request_cancel() what might happen is
that tb_cfg_request_work() completes right before tb_cfg_request_cancel()
starts and because of this it will call schedule_work() queueing the
same work to run again. However, it is already removed from the
request_queue and reference count is dropped so when
tb_cfg_request_work() triggers again it will access memory that is
already released.
Fix this so that we first make sure a cancelled request is not handed
away from tb_cfg_request_find() or scheduled to run. Then instead of
relying on the worker to clean up the request we will do it in
tb_cfg_request_cancel() after the work is canceled from running. Make
tb_cfg_request_dequeue() release the request only if it was actually
removed from the queue.
thunderbolt: Fix KASAN reported use-after-free when request is canceled
Alan reported that when doing stress testing sometimes KASAN notices
use-after-free during control channel operation (stripped down keeping
the relevant parts):
BUG: KASAN: slab-use-after-free in tb_cfg_request_sync+0x240/0x250 [thunderbolt]
Read of size 24 at addr ffff88811067f290 by task kworker/u40:2/1760
<TASK>
tb_cfg_request_sync+0x240/0x250 [thunderbolt]
tb_cfg_read_raw+0x367/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 1760:
__kmalloc_cache_noprof+0x1ee/0x550
tb_cfg_read_raw+0x1d3/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
Freed by task 926:
kfree+0x18f/0x4a0
tb_cfg_request_put+0xb7/0xe0 [thunderbolt]
tb_cfg_request_work+0x82/0x120 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
Second to last potentially related work creation:
__queue_work+0x575/0xd00
queue_work_on+0x77/0x80
tb_cfg_request_cancel+0xc7/0x260 [thunderbolt]
tb_cfg_request_sync+0x1f6/0x250 [thunderbolt]
tb_cfg_read_raw+0x367/0x510 [thunderbolt]
tb_cfg_read+0xec/0x240 [thunderbolt]
tb_port_get_link_generation+0x258/0x420 [thunderbolt]
tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]
tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]
tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]
tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]
tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]
process_one_work+0x675/0x1230
worker_thread+0x5e6/0xf70
kthread+0x365/0x470
ret_from_fork+0x54d/0x710
ret_from_fork_asm+0x1a/0x30
The last stack trace is helpful because it shows that we are cancelling
a request and looking at tb_cfg_request_cancel() what might happen is
that tb_cfg_request_work() completes right before tb_cfg_request_cancel()
starts and because of this it will call schedule_work() queueing the
same work to run again. However, it is already removed from the
request_queue and reference count is dropped so when
tb_cfg_request_work() triggers again it will access memory that is
already released.
Fix this so that we first make sure a cancelled request is not handed
away from tb_cfg_request_find() or scheduled to run. Then instead of
relying on the worker to clean up the request we will do it in
tb_cfg_request_cancel() after the work is canceled from running. Make
tb_cfg_request_dequeue() release the request only if it was actually
removed from the queue.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix KASAN reported use-after-free when request is canceled Alan reported that when doing stress testing sometimes KASAN notices use-after-free during control channel operation (stripped down keeping the relevant parts): BUG: KASAN: slab-use-after-free in tb_cfg_request_sync+0x240/0x250 [thunderbolt] Read of size 24 at addr ffff88811067f290 by task kworker/u40:2/1760 <TASK> tb_cfg_request_sync+0x240/0x250 [thunderbolt] tb_cfg_read_raw+0x367/0x510 [thunderbolt] tb_cfg_read+0xec/0x240 [thunderbolt] tb_port_get_link_generation+0x258/0x420 [thunderbolt] tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt] tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt] tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt] tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt] tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt] process_one_work+0x675/0x1230 worker_thread+0x5e6/0xf70 kthread+0x365/0x470 ret_from_fork+0x54d/0x710 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 1760: __kmalloc_cache_noprof+0x1ee/0x550 tb_cfg_read_raw+0x1d3/0x510 [thunderbolt] tb_cfg_read+0xec/0x240 [thunderbolt] tb_port_get_link_generation+0x258/0x420 [thunderbolt] tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt] tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt] tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt] tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt] tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt] process_one_work+0x675/0x1230 worker_thread+0x5e6/0xf70 kthread+0x365/0x470 ret_from_fork+0x54d/0x710 ret_from_fork_asm+0x1a/0x30 Freed by task 926: kfree+0x18f/0x4a0 tb_cfg_request_put+0xb7/0xe0 [thunderbolt] tb_cfg_request_work+0x82/0x120 [thunderbolt] process_one_work+0x675/0x1230 worker_thread+0x5e6/0xf70 kthread+0x365/0x470 ret_from_fork+0x54d/0x710 ret_from_fork_asm+0x1a/0x30 Second to last potentially related work creation: __queue_work+0x575/0xd00 queue_work_on+0x77/0x80 tb_cfg_request_cancel+0xc7/0x260 [thunderbolt] tb_cfg_request_sync+0x1f6/0x250 [thunderbolt] tb_cfg_read_raw+0x367/0x510 [thunderbolt] tb_cfg_read+0xec/0x240 [thunderbolt] tb_port_get_link_generation+0x258/0x420 [thunderbolt] tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt] tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt] tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt] tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt] tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt] process_one_work+0x675/0x1230 worker_thread+0x5e6/0xf70 kthread+0x365/0x470 ret_from_fork+0x54d/0x710 ret_from_fork_asm+0x1a/0x30 The last stack trace is helpful because it shows that we are cancelling a request and looking at tb_cfg_request_cancel() what might happen is that tb_cfg_request_work() completes right before tb_cfg_request_cancel() starts and because of this it will call schedule_work() queueing the same work to run again. However, it is already removed from the request_queue and reference count is dropped so when tb_cfg_request_work() triggers again it will access memory that is already released. Fix this so that we first make sure a cancelled request is not handed away from tb_cfg_request_find() or scheduled to run. Then instead of relying on the worker to clean up the request we will do it in tb_cfg_request_cancel() after the work is canceled from running. Make tb_cfg_request_dequeue() release the request only if it was actually removed from the queue. | |
| Title | thunderbolt: Fix KASAN reported use-after-free when request is canceled | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:46:18.654Z
Reserved: 2026-09-25T10:25:14.364Z
Link: CVE-2026-98694
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:22.830
Modified: 2026-10-18T16:17:22.830
Link: CVE-2026-98694
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.