Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5 thunderbolt tb_cfg_request_cancel use after free

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CTI Interest Score
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9.5$5k-$25k1.82

Summaryinfo

A vulnerability marked as very critical has been reported in Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5. Impacted is the function tb_cfg_request_cancel of the component thunderbolt. The manipulation leads to use after free. This vulnerability is listed as CVE-2026-98694. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.112/6.18.55/7.2.9/7.3-rc5 and classified as very critical. This issue affects the function tb_cfg_request_cancel of the component thunderbolt. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-98694 since 09/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/18/2026).

Upgrading to version 6.12.113, 6.18.56, 7.2.10 or 7.3-rc6 eliminates this vulnerability. Applying the patch 71b3c517e02af2c46ad58d4b3706b7c3cb24936d/f18faa3d3b810d60a3005ae1b1d1866faa67d343/08287212b622039212c972806f896f078dfd28e2/a02188ddc24b7872f0c5e0c5873f827318717803 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.113/6.18.56/7.2.10/7.3-rc6
Patch: 71b3c517e02af2c46ad58d4b3706b7c3cb24936d/f18faa3d3b810d60a3005ae1b1d1866faa67d343/08287212b622039212c972806f896f078dfd28e2/a02188ddc24b7872f0c5e0c5873f827318717803

Timelineinfo

09/25/2026 CVE reserved
10/18/2026 +23 days Advisory disclosed
10/18/2026 +0 days VulDB entry created
10/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98694 (🔒)
GCVE (CVE): GCVE-0-2026-98694
GCVE (VulDB): GCVE-100-421943

Entryinfo

Created: 10/18/2026 19:25
Changes: 10/18/2026 19:25 (59)
Complete: 🔍
Cache ID: 216::103

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