CVE-2026-98694
Status: ReceivedUnscored—
Severity—Unscored
Exploitation probability0.17 %higher than 6% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found
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):
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.
Read full descriptionShow less
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.
Technical details traces, logs and code from the original report
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
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.17 %
- Percentile among all scored CVEs
- 6
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 4 references
Raw JSON (NVD)
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{
"id": "CVE-2026-98694",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1",
"lessThan": "71b3c517e02af2c46ad58d4b3706b7c3cb24936d",
"versionType": "git"
},
{
"status": "affected",
"version": "d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1",
"lessThan": "f18faa3d3b810d60a3005ae1b1d1866faa67d343",
"versionType": "git"
},
{
"status": "affected",
"version": "d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1",
"lessThan": "08287212b622039212c972806f896f078dfd28e2",
"versionType": "git"
},
{
"status": "affected",
"version": "d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1",
"lessThan": "a02188ddc24b7872f0c5e0c5873f827318717803",
"versionType": "git"
}
],
"programFiles": [
"drivers/thunderbolt/ctl.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.56",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/thunderbolt/ctl.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:22.830",
"references": [
{
"url": "https://git.kernel.org/stable/c/08287212b622039212c972806f896f078dfd28e2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/71b3c517e02af2c46ad58d4b3706b7c3cb24936d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a02188ddc24b7872f0c5e0c5873f827318717803",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f18faa3d3b810d60a3005ae1b1d1866faa67d343",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix KASAN reported use-after-free when request is canceled\n\nAlan reported that when doing stress testing sometimes KASAN notices\nuse-after-free during control channel operation (stripped down keeping\nthe relevant parts):\n\n BUG: KASAN: slab-use-after-free in tb_cfg_request_sync+0x240/0x250 [thunderbolt]\n Read of size 24 at addr ffff88811067f290 by task kworker/u40:2/1760\n <TASK>\n tb_cfg_request_sync+0x240/0x250 [thunderbolt]\n tb_cfg_read_raw+0x367/0x510 [thunderbolt]\n tb_cfg_read+0xec/0x240 [thunderbolt]\n tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n process_one_work+0x675/0x1230\n worker_thread+0x5e6/0xf70\n kthread+0x365/0x470\n ret_from_fork+0x54d/0x710\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\n Allocated by task 1760:\n __kmalloc_cache_noprof+0x1ee/0x550\n tb_cfg_read_raw+0x1d3/0x510 [thunderbolt]\n tb_cfg_read+0xec/0x240 [thunderbolt]\n tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n process_one_work+0x675/0x1230\n worker_thread+0x5e6/0xf70\n kthread+0x365/0x470\n ret_from_fork+0x54d/0x710\n ret_from_fork_asm+0x1a/0x30\n\n Freed by task 926:\n kfree+0x18f/0x4a0\n tb_cfg_request_put+0xb7/0xe0 [thunderbolt]\n tb_cfg_request_work+0x82/0x120 [thunderbolt]\n process_one_work+0x675/0x1230\n worker_thread+0x5e6/0xf70\n kthread+0x365/0x470\n ret_from_fork+0x54d/0x710\n ret_from_fork_asm+0x1a/0x30\n\n Second to last potentially related work creation:\n __queue_work+0x575/0xd00\n queue_work_on+0x77/0x80\n tb_cfg_request_cancel+0xc7/0x260 [thunderbolt]\n tb_cfg_request_sync+0x1f6/0x250 [thunderbolt]\n tb_cfg_read_raw+0x367/0x510 [thunderbolt]\n tb_cfg_read+0xec/0x240 [thunderbolt]\n tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n process_one_work+0x675/0x1230\n worker_thread+0x5e6/0xf70\n kthread+0x365/0x470\n ret_from_fork+0x54d/0x710\n ret_from_fork_asm+0x1a/0x30\n\nThe last stack trace is helpful because it shows that we are cancelling\na request and looking at tb_cfg_request_cancel() what might happen is\nthat tb_cfg_request_work() completes right before tb_cfg_request_cancel()\nstarts and because of this it will call schedule_work() queueing the\nsame work to run again. However, it is already removed from the\nrequest_queue and reference count is dropped so when\ntb_cfg_request_work() triggers again it will access memory that is\nalready released.\n\nFix this so that we first make sure a cancelled request is not handed\naway from tb_cfg_request_find() or scheduled to run. Then instead of\nrelying on the worker to clean up the request we will do it in\ntb_cfg_request_cancel() after the work is canceled from running. Make\ntb_cfg_request_dequeue() release the request only if it was actually\nremoved from the queue."
}
],
"lastModified": "2026-10-19T10:19:33.730",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}