thunderbolt: Fix KASAN reported use-after-free when request is canceled
Summary
| CVE | CVE-2026-98694 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-18 16:17:22 UTC |
| Updated | 2026-10-21 13:21:37 UTC |
| 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. |
Risk And Classification
EPSS: 0.001680000 probability, percentile 0.057080000 (date 2026-10-21)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1 b70b9c41f240c42bf6e728034537c0fe60c16ef4 git | Not specified |
| CNA | Linux | Linux | affected d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1 71b3c517e02af2c46ad58d4b3706b7c3cb24936d git | Not specified |
| CNA | Linux | Linux | affected d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1 f18faa3d3b810d60a3005ae1b1d1866faa67d343 git | Not specified |
| CNA | Linux | Linux | affected d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1 08287212b622039212c972806f896f078dfd28e2 git | Not specified |
| CNA | Linux | Linux | affected d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1 a02188ddc24b7872f0c5e0c5873f827318717803 git | Not specified |
| CNA | Linux | Linux | affected 4.13 | Not specified |
| CNA | Linux | Linux | unaffected 4.13 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.160 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.113 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.56 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.10 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/08287212b622039212c972806f896f078dfd28e2 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/b70b9c41f240c42bf6e728034537c0fe60c16ef4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/71b3c517e02af2c46ad58d4b3706b7c3cb24936d | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f18faa3d3b810d60a3005ae1b1d1866faa67d343 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a02188ddc24b7872f0c5e0c5873f827318717803 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.