CVE-2023-53827 (GCVE-0-2023-53827)
Vulnerability from cvelistv5 – Published: 2025-12-09 01:29 – Updated: 2026-08-05 09:16
VLAI
EPSS
VEX
Title
Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}
Summary
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}
Similar to commit d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free
caused by l2cap_chan_put"), just use l2cap_chan_hold_unless_zero to
prevent referencing a channel that is about to be destroyed.
Severity
8.8 (High)
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < f2d38e77aa5f3effc143e7dd24da8acf02925958
(git)
Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < 1351551aa9058e07a20a27a158270cf84fcde621 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < c02421992505c95c7f3c9ad59ee35e22eac60988 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < d9ba36c22a7bb09d6bac4cc2f243eff05da53f43 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < ac6725a634f7e8c0330610a8527f20c730b61115 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < 348d446762e7c70778df8bafbdf3fa0df2123f58 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < d82a439c3cfdb28aa7e82e2e849c5c4dd9fca284 (git) Affected: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943 , < a2a9339e1c9deb7e1e079e12e27a0265aea8421a (git) |
guessed | |
| Linux | Linux |
Affected:
3.5
Unaffected: 0 , < 3.5 (semver) Unaffected: 4.14.313 , ≤ 4.14.* (semver) Unaffected: 4.19.281 , ≤ 4.19.* (semver) Unaffected: 5.4.241 , ≤ 5.4.* (semver) Unaffected: 5.10.178 , ≤ 5.10.* (semver) Unaffected: 5.15.108 , ≤ 5.15.* (semver) Unaffected: 6.1.25 , ≤ 6.1.* (semver) Unaffected: 6.2.12 , ≤ 6.2.* (semver) Unaffected: 6.3 , ≤ * (original_commit_for_fix) |
guessed |
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"programFiles": [
"net/bluetooth/l2cap_core.c"
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{
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{
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},
{
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}
],
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{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}\n\nSimilar to commit d0be8347c623 (\"Bluetooth: L2CAP: Fix use-after-free\ncaused by l2cap_chan_put\"), just use l2cap_chan_hold_unless_zero to\nprevent referencing a channel that is about to be destroyed."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - The vulnerable code is reached only by processing an L2CAP Disconnect Request/Response signalling PDU received from a Bluetooth peer over a BR/EDR ACL or LE link, which requires the attacker to be within Bluetooth radio range. Per kernel scoring guidance, Bluetooth-reachable code is Adjacent.\nAC:L - The attacker drives both sides: it creates and tears down L2CAP channels at will (CONN_REQ/DISCONN_REQ, ECRED reconfigure responses that call l2cap_chan_del with no lock) while flooding disconnect signalling to hit the window where the kref has reached zero but the channel is still on conn-\u003echan_l, and can retry the connect/disconnect cycle indefinitely at no cost. syzbot reproduced the identical pattern in the sibling handler.\nPR:N - l2cap_recv_frame dispatches CID 0x0001/0x0005 straight to the signalling handlers with no security-level, pairing, or encryption check, so an entirely unauthenticated, unpaired in-range device can send the triggering PDU. Fixed channels present on conn-\u003echan_l give a valid target CID without any local socket.\nUI:N - No victim action is needed \u2014 the packet is processed by hci_rx_work as soon as it arrives on a connectable/advertising host with Bluetooth enabled, which is the default on phones, cars, headsets and laptops.\nS:U - The corruption and its consequences are confined to the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The handler reads chan-\u003escid and chan-\u003edcid out of the freed kmalloc-1k object and echoes them to the attacker in the Disconnect Response, giving a repeatable remote leak of reclaimed kernel heap contents, and the broader use-after-free permits arbitrary read via heap grooming.\nI:H - After the increment-on-zero the code performs three indirect calls (chan-\u003eops-\u003eset_shutdown, -\u003eteardown, -\u003eclose) through function pointers read from the freed object plus a list_del on freed list heads, so an attacker who sprays the reclaimed kmalloc-1024 slot obtains control-flow hijack and arbitrary-write primitives.\nA:H - The bug is a KASAN-confirmed use-after-free that mutex_locks freed memory and triggers a refcount_t \"increment on 0\" splat, reliably producing a kernel oops/panic, and it can be re-triggered remotely at will."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T09:16:16.899Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/f2d38e77aa5f3effc143e7dd24da8acf02925958"
},
{
"url": "https://git.kernel.org/stable/c/1351551aa9058e07a20a27a158270cf84fcde621"
},
{
"url": "https://git.kernel.org/stable/c/c02421992505c95c7f3c9ad59ee35e22eac60988"
},
{
"url": "https://git.kernel.org/stable/c/d9ba36c22a7bb09d6bac4cc2f243eff05da53f43"
},
{
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},
{
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},
{
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},
{
"url": "https://git.kernel.org/stable/c/a2a9339e1c9deb7e1e079e12e27a0265aea8421a"
}
],
"title": "Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}",
"x_generator": {
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}
}
},
"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2023-53827",
"datePublished": "2025-12-09T01:29:40.794Z",
"dateReserved": "2025-12-09T01:27:17.825Z",
"dateUpdated": "2026-08-05T09:16:16.899Z",
"state": "PUBLISHED"
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"date": "2026-09-19",
"epss": "0.00391",
"percentile": "0.33037"
},
"nvd": {
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{
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"versionType": "semver"
},
{
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"status": "unaffected",
"version": "4.19.281",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"version": "5.4.241",
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},
{
"lessThanOrEqual": "5.10.*",
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{
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"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.25",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.2.*",
"status": "unaffected",
"version": "6.2.12",
"versionType": "semver"
},
{
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"version": "6.3",
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}
]
}
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}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}\n\nSimilar to commit d0be8347c623 (\"Bluetooth: L2CAP: Fix use-after-free\ncaused by l2cap_chan_put\"), just use l2cap_chan_hold_unless_zero to\nprevent referencing a channel that is about to be destroyed."
}
],
"id": "CVE-2023-53827",
"lastModified": "2026-08-04T10:19:23.187",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2025-12-09T16:17:21.570",
"references": [
{
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"url": "https://git.kernel.org/stable/c/1351551aa9058e07a20a27a158270cf84fcde621"
},
{
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"url": "https://git.kernel.org/stable/c/348d446762e7c70778df8bafbdf3fa0df2123f58"
},
{
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"url": "https://git.kernel.org/stable/c/a2a9339e1c9deb7e1e079e12e27a0265aea8421a"
},
{
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"url": "https://git.kernel.org/stable/c/ac6725a634f7e8c0330610a8527f20c730b61115"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c02421992505c95c7f3c9ad59ee35e22eac60988"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d82a439c3cfdb28aa7e82e2e849c5c4dd9fca284"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d9ba36c22a7bb09d6bac4cc2f243eff05da53f43"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f2d38e77aa5f3effc143e7dd24da8acf02925958"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-08-04T19:16:34+00:00",
"cve": "CVE-2023-53827",
"id": "CVE-2023-53827",
"initial_release_date": "2023-01-01T00:00:00+00:00",
"product_status:fixed": "75",
"product_status:known_affected": "76",
"product_status:known_not_affected": "198",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53827.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-08-31T00:55:26Z",
"cve": "CVE-2023-53827",
"id": "CVE-2023-53827",
"initial_release_date": "2025-12-10T00:35:19Z",
"product_status:known_affected": "354",
"product_status:known_not_affected": "330",
"product_status:recommended": "237",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2023-53827",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2023-53827.json",
"version": "24"
}
}
}
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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.
- 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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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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