FKIE_CVE-2025-68304
Vulnerability from fkie_nvd - Published: 2025-12-16 16:16 - Updated: 2026-06-17 09:58
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: lookup hci_conn on RX path on protocol side
The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't
ensure hci_conn* is not concurrently modified/deleted. This locking
appears to be leftover from before conn_hash started using RCU
commit bf4c63252490b ("Bluetooth: convert conn hash to RCU")
and not clear if it had purpose since then.
Currently, there are code paths that delete hci_conn* from elsewhere
than the ordered hdev->workqueue where the RX work runs in. E.g.
commit 5af1f84ed13a ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync")
introduced some of these, and there probably were a few others before
it. It's better to do the locking so that even if these run
concurrently no UAF is possible.
Move the lookup of hci_conn and associated socket-specific conn to
protocol recv handlers, and do them within a single critical section
to cover hci_conn* usage and lookup.
syzkaller has reported a crash that appears to be this issue:
[Task hdev->workqueue] [Task 2]
hci_disconnect_all_sync
l2cap_recv_acldata(hcon)
hci_conn_get(hcon)
hci_abort_conn_sync(hcon)
hci_dev_lock
hci_dev_lock
hci_conn_del(hcon)
v-------------------------------- hci_dev_unlock
hci_conn_put(hcon)
conn = hcon->l2cap_data (UAF)
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/bluetooth/hci_core.h",
"net/bluetooth/hci_core.c",
"net/bluetooth/iso.c",
"net/bluetooth/l2cap_core.c",
"net/bluetooth/sco.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93",
"status": "affected",
"version": "5af1f84ed13a416297ab9ced7537f4d5ae7f329a",
"versionType": "git"
},
{
"lessThan": "79a2d4678ba90bdba577dc3af88cc900d6dcd5ee",
"status": "affected",
"version": "5af1f84ed13a416297ab9ced7537f4d5ae7f329a",
"versionType": "git"
},
{
"status": "affected",
"version": "cd55c13bbb3d093ae601aa97e588ed4c1390ebb1",
"versionType": "git"
},
{
"status": "affected",
"version": "4d3ca4a9aaf0aa798a6be372dc0fc3a29e37dd57",
"versionType": "git"
},
{
"status": "affected",
"version": "80265dd1d944c3f33e52375b5dbe654980bd2688",
"versionType": "git"
},
{
"lessThan": "6.2",
"status": "affected",
"version": "6.1.149",
"versionType": "semver"
},
{
"lessThan": "6.5",
"status": "affected",
"version": "6.4.16",
"versionType": "semver"
},
{
"lessThan": "6.6",
"status": "affected",
"version": "6.5.3",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/bluetooth/hci_core.h",
"net/bluetooth/hci_core.c",
"net/bluetooth/iso.c",
"net/bluetooth/l2cap_core.c",
"net/bluetooth/sco.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"lessThan": "6.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.17.*",
"status": "unaffected",
"version": "6.17.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: lookup hci_conn on RX path on protocol side\n\nThe hdev lock/lookup/unlock/use pattern in the packet RX path doesn\u0027t\nensure hci_conn* is not concurrently modified/deleted. This locking\nappears to be leftover from before conn_hash started using RCU\ncommit bf4c63252490b (\"Bluetooth: convert conn hash to RCU\")\nand not clear if it had purpose since then.\n\nCurrently, there are code paths that delete hci_conn* from elsewhere\nthan the ordered hdev-\u003eworkqueue where the RX work runs in. E.g.\ncommit 5af1f84ed13a (\"Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync\")\nintroduced some of these, and there probably were a few others before\nit. It\u0027s better to do the locking so that even if these run\nconcurrently no UAF is possible.\n\nMove the lookup of hci_conn and associated socket-specific conn to\nprotocol recv handlers, and do them within a single critical section\nto cover hci_conn* usage and lookup.\n\nsyzkaller has reported a crash that appears to be this issue:\n\n [Task hdev-\u003eworkqueue] [Task 2]\n hci_disconnect_all_sync\n l2cap_recv_acldata(hcon)\n hci_conn_get(hcon)\n hci_abort_conn_sync(hcon)\n hci_dev_lock\n hci_dev_lock\n hci_conn_del(hcon)\n v-------------------------------- hci_dev_unlock\n hci_conn_put(hcon)\n conn = hcon-\u003el2cap_data (UAF)"
}
],
"id": "CVE-2025-68304",
"lastModified": "2026-06-17T09:58:54.203",
"metrics": {},
"published": "2025-12-16T16:16:09.930",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/79a2d4678ba90bdba577dc3af88cc900d6dcd5ee"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
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- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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