FKIE_CVE-2026-43023
Vulnerability from fkie_nvd - Published: 2026-05-01 15:16 - Updated: 2026-06-17 10:48
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: SCO: fix race conditions in sco_sock_connect()
sco_sock_connect() checks sk_state and sk_type without holding
the socket lock. Two concurrent connect() syscalls on the same
socket can both pass the check and enter sco_connect(), leading
to use-after-free.
The buggy scenario involves three participants and was confirmed
with additional logging instrumentation:
Thread A (connect): HCI disconnect: Thread B (connect):
sco_sock_connect(sk) sco_sock_connect(sk)
sk_state==BT_OPEN sk_state==BT_OPEN
(pass, no lock) (pass, no lock)
sco_connect(sk): sco_connect(sk):
hci_dev_lock hci_dev_lock
hci_connect_sco <- blocked
-> hcon1
sco_conn_add->conn1
lock_sock(sk)
sco_chan_add:
conn1->sk = sk
sk->conn = conn1
sk_state=BT_CONNECT
release_sock
hci_dev_unlock
hci_dev_lock
sco_conn_del:
lock_sock(sk)
sco_chan_del:
sk->conn=NULL
conn1->sk=NULL
sk_state=
BT_CLOSED
SOCK_ZAPPED
release_sock
hci_dev_unlock
(unblocked)
hci_connect_sco
-> hcon2
sco_conn_add
-> conn2
lock_sock(sk)
sco_chan_add:
sk->conn=conn2
sk_state=
BT_CONNECT
// zombie sk!
release_sock
hci_dev_unlock
Thread B revives a BT_CLOSED + SOCK_ZAPPED socket back to
BT_CONNECT. Subsequent cleanup triggers double sock_put() and
use-after-free. Meanwhile conn1 is leaked as it was orphaned
when sco_conn_del() cleared the association.
Fix this by:
- Moving lock_sock() before the sk_state/sk_type checks in
sco_sock_connect() to serialize concurrent connect attempts
- Fixing the sk_type != SOCK_SEQPACKET check to actually
return the error instead of just assigning it
- Adding a state re-check in sco_connect() after lock_sock()
to catch state changes during the window between the locks
- Adding sco_pi(sk)->conn check in sco_chan_add() to prevent
double-attach of a socket to multiple connections
- Adding hci_conn_drop() on sco_chan_add failure to prevent
HCI connection leaks
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 6.3 | |
| linux | linux_kernel | 6.3 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bluetooth/sco.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "70a13b1e25fef37c87c8a1228ddb8900efbca7cf",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
"version": "9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3",
"versionType": "git"
},
{
"lessThan": "d002bd11024bd231bcb606877e33951ffb7bed14",
"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
"version": "9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3",
"versionType": "git"
},
{
"lessThan": "6.1.168",
"status": "affected",
"version": "6.1.109",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bluetooth/sco.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
"lessThan": "6.3",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.168",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.134",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.81",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.22",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.12",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
"nodes": [
{
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: SCO: fix race conditions in sco_sock_connect()\n\nsco_sock_connect() checks sk_state and sk_type without holding\nthe socket lock. Two concurrent connect() syscalls on the same\nsocket can both pass the check and enter sco_connect(), leading\nto use-after-free.\n\nThe buggy scenario involves three participants and was confirmed\nwith additional logging instrumentation:\n\n Thread A (connect): HCI disconnect: Thread B (connect):\n\n sco_sock_connect(sk) sco_sock_connect(sk)\n sk_state==BT_OPEN sk_state==BT_OPEN\n (pass, no lock) (pass, no lock)\n sco_connect(sk): sco_connect(sk):\n hci_dev_lock hci_dev_lock\n hci_connect_sco \u003c- blocked\n -\u003e hcon1\n sco_conn_add-\u003econn1\n lock_sock(sk)\n sco_chan_add:\n conn1-\u003esk = sk\n sk-\u003econn = conn1\n sk_state=BT_CONNECT\n release_sock\n hci_dev_unlock\n hci_dev_lock\n sco_conn_del:\n lock_sock(sk)\n sco_chan_del:\n sk-\u003econn=NULL\n conn1-\u003esk=NULL\n sk_state=\n BT_CLOSED\n SOCK_ZAPPED\n release_sock\n hci_dev_unlock\n (unblocked)\n hci_connect_sco\n -\u003e hcon2\n sco_conn_add\n -\u003e conn2\n lock_sock(sk)\n sco_chan_add:\n sk-\u003econn=conn2\n sk_state=\n BT_CONNECT\n // zombie sk!\n release_sock\n hci_dev_unlock\n\nThread B revives a BT_CLOSED + SOCK_ZAPPED socket back to\nBT_CONNECT. Subsequent cleanup triggers double sock_put() and\nuse-after-free. Meanwhile conn1 is leaked as it was orphaned\nwhen sco_conn_del() cleared the association.\n\nFix this by:\n- Moving lock_sock() before the sk_state/sk_type checks in\n sco_sock_connect() to serialize concurrent connect attempts\n- Fixing the sk_type != SOCK_SEQPACKET check to actually\n return the error instead of just assigning it\n- Adding a state re-check in sco_connect() after lock_sock()\n to catch state changes during the window between the locks\n- Adding sco_pi(sk)-\u003econn check in sco_chan_add() to prevent\n double-attach of a socket to multiple connections\n- Adding hci_conn_drop() on sco_chan_add failure to prevent\n HCI connection leaks"
}
],
"id": "CVE-2026-43023",
"lastModified": "2026-06-17T10:48:47.027",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-05-01T15:16:46.610",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/7e296ffdab5bdab718dff7c14288fdcb9154fa27"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/8a5b0135d4a5d9683203a3d9a12a711ccec5936b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/d002bd11024bd231bcb606877e33951ffb7bed14"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/dabf22269242e2f2bf44c43fcdc2fa763df7f9cc"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-362"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- 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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