CVE-2026-99239
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_chan_del cleanup. There is a TOCTOU race where the invariant is violated: [Task 1] [Task 2] l2cap_chan_connect l2cap_sock_bind l2cap_chan_lock lock_sock l2cap_state_change if (sk->sk_state != BT_OPEN) chan->state = BT_CONNECT l2cap_sock_state_change_cb chan->state = BT_BOUND sk->sk_state = BT_BOUND lock_sock <------------------ release_sock sk->sk_state = BT_CONNECT l2cap_sock_connect() does not check sk->sk_state, so since chan->state is now BT_BOUND, subsequent connect() ends up with second __l2cap_chan_add. Explicitly document and check the invariant in __l2cap_chan_add with WARN_ON_ONCE. The only callsite where it could be hit is l2cap_chan_connect, so add pre-check there to avoid relying on chan->state. chan->state read/write is not properly guarded currently so there can be other TOCTOUC problems. Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-11-02 16:17:49.540000
Last modified
2026-11-02 16:17:49.540000
View original CVE JSON
{
"id": "CVE-2026-99239",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-11-02T16:17:49.540",
"lastModified": "2026-11-02T16:17:49.540",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn\n\nl2cap_chan may be linked to l2cap_conn at most once. This is assumed in\nseveral places, eg l2cap_chan_del cleanup.\n\nThere is a TOCTOU race where the invariant is violated:\n\n [Task 1] [Task 2]\n l2cap_chan_connect l2cap_sock_bind\n l2cap_chan_lock lock_sock\n l2cap_state_change if (sk->sk_state != BT_OPEN)\n chan->state = BT_CONNECT\n l2cap_sock_state_change_cb chan->state = BT_BOUND\n sk->sk_state = BT_BOUND\n lock_sock <------------------ release_sock\n sk->sk_state = BT_CONNECT\n\nl2cap_sock_connect() does not check sk->sk_state, so since chan->state\nis now BT_BOUND, subsequent connect() ends up with second\n__l2cap_chan_add.\n\nExplicitly document and check the invariant in __l2cap_chan_add with\nWARN_ON_ONCE. The only callsite where it could be hit is\nl2cap_chan_connect, so add pre-check there to avoid relying on\nchan->state. chan->state read/write is not properly guarded currently so\nthere can be other TOCTOUC problems.\n\nAdd l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/bluetooth/l2cap_core.c",
"net/bluetooth/l2cap_sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
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"versionType": "git",
"status": "affected"
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{
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{
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{
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},
{
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"versionType": "semver",
"status": "affected"
},
{
"version": "6.1.183",
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},
{
"version": "6.6.145",
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},
{
"version": "6.12.97",
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},
{
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]
},
{
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"product": "Linux",
"defaultStatus": "affected",
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"net/bluetooth/l2cap_sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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},
{
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"status": "unaffected"
},
{
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"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.224",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.191",
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},
{
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},
{
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},
{
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},
{
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"lessThanOrEqual": "7.2.*",
"versionType": "semver",
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},
{
"version": "7.3.1",
"lessThanOrEqual": "7.3.*",
"versionType": "semver",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/10c705dd706aa93164ba41f2566f15206d6c178e",
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}