FKIE_CVE-2026-90091
Vulnerability from fkie_nvd - Published: 2026-09-17 17:17 - Updated: 2026-09-18 18:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan
For L2CAP sockets without owning sk->sk_socket, reading
l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() ->
l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks,
but access in l2cap_sock_cleanup_listen() has unsafe lockless read.
[Task 1] [Task 2 (hdev->workqueue)]
l2cap_sock_release(parent) l2cap_disconn_cfm
l2cap_sock_cleanup_listen l2cap_conn_del
bt_accept_dequeue l2cap_chan_del
lock_sock(sk) l2cap_sock_teardown_cb
bt_accept_unlink
bt_sk(sk)->parent = NULL
release_sock(sk) ----------------> lock_sock(sk)
parent = /* NULL */
lock_sock(sk) <--------------------- release_sock(sk)
sock_set_flag(sk, SOCK_ZAPPED)
l2cap_sock_close_cb
l2cap_sock_kill(sk)
l2cap_sock_put_chan
chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL
l2cap_chan_hold_unless_zero l2cap_put_chan(chan)
kref_get_unless_zero(&chan->ref)
Task 1 may observe NULL which causes null-ptr-deref.
Fix the race by taking lock_sock() in l2cap_sock_kill() to
synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not
needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL.
Clarify code comments vs. locking.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/bluetooth/l2cap.h",
"net/bluetooth/l2cap_sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "827de6bd2865b22aaabd554540def3b8a33018ab",
"status": "affected",
"version": "b39298044e5534612511a2ff5de03ba5f6e7a820",
"versionType": "git"
},
{
"lessThan": "7c7ac736b50fa259ed1bdddc18d79523f07c0442",
"status": "affected",
"version": "8c37e4338c801ebb8cee52436c01c41e009f6e87",
"versionType": "git"
},
{
"lessThan": "4f8c63fe0097c9f6ea34409f82f79b3894903d91",
"status": "affected",
"version": "84e718b6a814edc84159361f9f454a4e92ae91ae",
"versionType": "git"
},
{
"lessThan": "61d5ddbd524c715b224cbe7e9f01da4e05098b19",
"status": "affected",
"version": "36da806f7fbaee56ad9e81859deec203f9728700",
"versionType": "git"
},
{
"lessThan": "32a7bc6e93be36b37fe61f351d312d358195bd61",
"status": "affected",
"version": "6fef032af0092ed5ccb767239a9ac1bc38c08a40",
"versionType": "git"
},
{
"lessThan": "66d6ef18548ae6d7dd452b84115fc82c0a73a4ea",
"status": "affected",
"version": "6fef032af0092ed5ccb767239a9ac1bc38c08a40",
"versionType": "git"
},
{
"status": "affected",
"version": "733e76e74e406c1d1ddc7369420dd8a47f48bb8a",
"versionType": "git"
},
{
"lessThan": "6.1.188",
"status": "affected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThan": "6.6.157",
"status": "affected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThan": "6.12.110",
"status": "affected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThan": "6.18.52",
"status": "affected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThan": "7.2",
"status": "affected",
"version": "7.1.5",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/bluetooth/l2cap.h",
"net/bluetooth/l2cap_sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"lessThan": "7.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"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: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan\n\nFor L2CAP sockets without owning sk-\u003esk_socket, reading\nl2cap_pi(sk)-\u003echan may race against concurrent l2cap_sock_kill() -\u003e\nl2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks,\nbut access in l2cap_sock_cleanup_listen() has unsafe lockless read.\n\n [Task 1] [Task 2 (hdev-\u003eworkqueue)]\n l2cap_sock_release(parent) l2cap_disconn_cfm\n l2cap_sock_cleanup_listen l2cap_conn_del\n bt_accept_dequeue l2cap_chan_del\n lock_sock(sk) l2cap_sock_teardown_cb\n bt_accept_unlink\n bt_sk(sk)-\u003eparent = NULL\n release_sock(sk) ----------------\u003e lock_sock(sk)\n parent = /* NULL */\n lock_sock(sk) \u003c--------------------- release_sock(sk)\n sock_set_flag(sk, SOCK_ZAPPED)\n l2cap_sock_close_cb\n l2cap_sock_kill(sk)\n l2cap_sock_put_chan\n chan = READ l2cap_pi(sk)-\u003echan l2cap_pi(sk)-\u003echan = NULL\n l2cap_chan_hold_unless_zero l2cap_put_chan(chan)\n kref_get_unless_zero(\u0026chan-\u003eref)\n\nTask 1 may observe NULL which causes null-ptr-deref.\n\nFix the race by taking lock_sock() in l2cap_sock_kill() to\nsynchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not\nneeded here, l2cap_pi(sk)-\u003echan owns reference if it is non-NULL.\n\nClarify code comments vs. locking."
}
],
"id": "CVE-2026-90091",
"lastModified": "2026-09-18T18:17:41.277",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.0,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.1,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-17T17:17:00.563",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/32a7bc6e93be36b37fe61f351d312d358195bd61"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4f8c63fe0097c9f6ea34409f82f79b3894903d91"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/61d5ddbd524c715b224cbe7e9f01da4e05098b19"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/66d6ef18548ae6d7dd452b84115fc82c0a73a4ea"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7c7ac736b50fa259ed1bdddc18d79523f07c0442"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/827de6bd2865b22aaabd554540def3b8a33018ab"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
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- 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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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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