Vulnerability-Lookup

GHSA-H7JM-4XPC-FCGR

Vulnerability from github – Published: 2026-10-18 18:32 – Updated: 2026-10-30 15:33

Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_core: Serialize ACL scheduling with channel deletion

hci_chan_sent() selects a channel under RCU but drops the read lock before accessing chan->conn and returning the channel. The ACL and LE schedulers then use its packet queue and update its transmit counters without any protection against channel deletion.

After TX selects a channel and releases RCU, a disconnect command timeout on the separate request workqueue can run hci_conn_failed() and l2cap_conn_del(). hci_chan_del() can then unlink the channel, complete synchronize_rcu(), purge its queue and free it before TX resumes. This causes use-after-free both in hci_chan_sent() and in its callers.

KASAN reported:

BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0 Workqueue: hci0 hci_tx_work Call Trace: hci_chan_sent+0x892/0x9b0 hci_tx_work+0x5e6/0xb70 Allocated by task 91: hci_chan_create+0xe3/0x350 l2cap_conn_add.part.0+0x12/0xa30 l2cap_chan_connect+0x110d/0x1b60 l2cap_sock_connect+0x310/0x530 Freed by task 99: hci_chan_del+0x11f/0x170 l2cap_conn_del+0x4f1/0x800 l2cap_connect_cfm+0x88c/0xd30 hci_conn_failed+0x150/0x250 hci_abort_conn_sync+0x3e3/0x800 hci_cmd_sync_run+0x7e/0xc0 hci_abort_conn+0x105/0x1f0 disconnect_sync+0x157/0x290 hci_cmd_sync_work+0x13c/0x290

Hold the existing device mutex across channel selection and transmission in both schedulers to serialize them with channel teardown. Keep timeout handling outside the critical sections because hci_link_tx_to() acquires the same mutex. This also permits the transmit path to sleep, unlike extending the RCU read-side critical section across packet submission.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98735"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:27Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: Serialize ACL scheduling with channel deletion\n\nhci_chan_sent() selects a channel under RCU but drops the read lock before\naccessing chan-\u003econn and returning the channel. The ACL and LE schedulers\nthen use its packet queue and update its transmit counters without any\nprotection against channel deletion.\n\nAfter TX selects a channel and releases RCU, a disconnect command timeout\non the separate request workqueue can run hci_conn_failed() and\nl2cap_conn_del(). hci_chan_del() can then unlink the channel, complete\nsynchronize_rcu(), purge its queue and free it before TX resumes. This\ncauses use-after-free both in hci_chan_sent() and in its callers.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0\n  Workqueue: hci0 hci_tx_work\n  Call Trace:\n   hci_chan_sent+0x892/0x9b0\n   hci_tx_work+0x5e6/0xb70\n  Allocated by task 91:\n   hci_chan_create+0xe3/0x350\n   l2cap_conn_add.part.0+0x12/0xa30\n   l2cap_chan_connect+0x110d/0x1b60\n   l2cap_sock_connect+0x310/0x530\n  Freed by task 99:\n   hci_chan_del+0x11f/0x170\n   l2cap_conn_del+0x4f1/0x800\n   l2cap_connect_cfm+0x88c/0xd30\n   hci_conn_failed+0x150/0x250\n   hci_abort_conn_sync+0x3e3/0x800\n   hci_cmd_sync_run+0x7e/0xc0\n   hci_abort_conn+0x105/0x1f0\n   disconnect_sync+0x157/0x290\n   hci_cmd_sync_work+0x13c/0x290\n\nHold the existing device mutex across channel selection and transmission\nin both schedulers to serialize them with channel teardown. Keep timeout\nhandling outside the critical sections because hci_link_tx_to() acquires\nthe same mutex. This also permits the transmit path to sleep, unlike\nextending the RCU read-side critical section across packet submission.",
  "id": "GHSA-h7jm-4xpc-fcgr",
  "modified": "2026-10-30T15:33:58Z",
  "published": "2026-10-18T18:32:01Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98735"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/126714c495bf31a5e71411b8e0b65a685bb5e58d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4fda8f0abeea9929036446d89a476fb8298abcb0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/51f95ea451f25d7e3f048c0f438f04fa74688aae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/74667f6eb7c12b65c56e02e0f527e4099db4ebfd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/780affacd92977fd9b819bdc4f26a6832cb27fda"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7fbeda3dcd5f54e7429f4b5e2cfa7344b7e9b1c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f4845ab191a4f686a5da481fbba90ed73bb693b0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98735 (GCVE-0-2026-98735)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:47 – Updated: 2026-10-30 12:39

Title

Bluetooth: hci_core: Serialize ACL scheduling with channel deletion

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Serialize ACL scheduling with channel deletion hci_chan_sent() selects a channel under RCU but drops the read lock before accessing chan->conn and returning the channel. The ACL and LE schedulers then use its packet queue and update its transmit counters without any protection against channel deletion. After TX selects a channel and releases RCU, a disconnect command timeout on the separate request workqueue can run hci_conn_failed() and l2cap_conn_del(). hci_chan_del() can then unlink the channel, complete synchronize_rcu(), purge its queue and free it before TX resumes. This causes use-after-free both in hci_chan_sent() and in its callers. KASAN reported: BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0 Workqueue: hci0 hci_tx_work Call Trace: hci_chan_sent+0x892/0x9b0 hci_tx_work+0x5e6/0xb70 Allocated by task 91: hci_chan_create+0xe3/0x350 l2cap_conn_add.part.0+0x12/0xa30 l2cap_chan_connect+0x110d/0x1b60 l2cap_sock_connect+0x310/0x530 Freed by task 99: hci_chan_del+0x11f/0x170 l2cap_conn_del+0x4f1/0x800 l2cap_connect_cfm+0x88c/0xd30 hci_conn_failed+0x150/0x250 hci_abort_conn_sync+0x3e3/0x800 hci_cmd_sync_run+0x7e/0xc0 hci_abort_conn+0x105/0x1f0 disconnect_sync+0x157/0x290 hci_cmd_sync_work+0x13c/0x290 Hold the existing device mutex across channel selection and transmission in both schedulers to serialize them with channel teardown. Keep timeout handling outside the critical sections because hci_link_tx_to() acquires the same mutex. This also permits the transmit path to sleep, unlike extending the RCU read-side critical section across packet submission.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6820 records in the last 180 days details

References

8 references

URL	Tags
https://git.kernel.org/stable/c/126714c495bf31a5e…
https://git.kernel.org/stable/c/7fbeda3dcd5f54e74…
https://git.kernel.org/stable/c/74667f6eb7c12b65c…
https://git.kernel.org/stable/c/780affacd92977fd9…
https://git.kernel.org/stable/c/51f95ea451f25d7e3…
https://git.kernel.org/stable/c/86e9708f9d19a7f1b…
https://git.kernel.org/stable/c/4fda8f0abeea99290…
https://git.kernel.org/stable/c/f4845ab191a4f686a…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 126714c495bf31a5e71411b8e0b65a685bb5e58d (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 7fbeda3dcd5f54e7429f4b5e2cfa7344b7e9b1c9 (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 74667f6eb7c12b65c56e02e0f527e4099db4ebfd (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 780affacd92977fd9b819bdc4f26a6832cb27fda (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 51f95ea451f25d7e3f048c0f438f04fa74688aae (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < 4fda8f0abeea9929036446d89a476fb8298abcb0 (git) Affected: 3eff45eaf81780dad25c167bbaafa7d25ae407da , < f4845ab191a4f686a5da481fbba90ed73bb693b0 (git)
Linux	Linux	Affected: 3.3 Unaffected: 0 , < 3.3 (semver) Unaffected: 5.10.273 , ≤ 5.10.* (semver) Unaffected: 5.15.224 , ≤ 5.15.* (semver) Unaffected: 6.1.191 , ≤ 6.1.* (semver) Unaffected: 6.6.160 , ≤ 6.6.* (semver) Unaffected: 6.12.113 , ≤ 6.12.* (semver) Unaffected: 6.18.56 , ≤ 6.18.* (semver) Unaffected: 7.2.10 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "126714c495bf31a5e71411b8e0b65a685bb5e58d",
              "status": "affected",
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              "versionType": "git"
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            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "74667f6eb7c12b65c56e02e0f527e4099db4ebfd",
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              "versionType": "git"
            },
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            {
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.3"
            },
            {
              "lessThan": "3.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.273",
                  "versionStartIncluding": "3.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
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                {
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                  "versionStartIncluding": "3.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                {
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: Serialize ACL scheduling with channel deletion\n\nhci_chan_sent() selects a channel under RCU but drops the read lock before\naccessing chan-\u003econn and returning the channel. The ACL and LE schedulers\nthen use its packet queue and update its transmit counters without any\nprotection against channel deletion.\n\nAfter TX selects a channel and releases RCU, a disconnect command timeout\non the separate request workqueue can run hci_conn_failed() and\nl2cap_conn_del(). hci_chan_del() can then unlink the channel, complete\nsynchronize_rcu(), purge its queue and free it before TX resumes. This\ncauses use-after-free both in hci_chan_sent() and in its callers.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0\n  Workqueue: hci0 hci_tx_work\n  Call Trace:\n   hci_chan_sent+0x892/0x9b0\n   hci_tx_work+0x5e6/0xb70\n  Allocated by task 91:\n   hci_chan_create+0xe3/0x350\n   l2cap_conn_add.part.0+0x12/0xa30\n   l2cap_chan_connect+0x110d/0x1b60\n   l2cap_sock_connect+0x310/0x530\n  Freed by task 99:\n   hci_chan_del+0x11f/0x170\n   l2cap_conn_del+0x4f1/0x800\n   l2cap_connect_cfm+0x88c/0xd30\n   hci_conn_failed+0x150/0x250\n   hci_abort_conn_sync+0x3e3/0x800\n   hci_cmd_sync_run+0x7e/0xc0\n   hci_abort_conn+0x105/0x1f0\n   disconnect_sync+0x157/0x290\n   hci_cmd_sync_work+0x13c/0x290\n\nHold the existing device mutex across channel selection and transmission\nin both schedulers to serialize them with channel teardown. Keep timeout\nhandling outside the critical sections because hci_link_tx_to() acquires\nthe same mutex. This also permits the transmit path to sleep, unlike\nextending the RCU read-side critical section across packet submission."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:39:11.976Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/126714c495bf31a5e71411b8e0b65a685bb5e58d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7fbeda3dcd5f54e7429f4b5e2cfa7344b7e9b1c9"
        },
        {
          "url": "https://git.kernel.org/stable/c/74667f6eb7c12b65c56e02e0f527e4099db4ebfd"
        },
        {
          "url": "https://git.kernel.org/stable/c/780affacd92977fd9b819bdc4f26a6832cb27fda"
        },
        {
          "url": "https://git.kernel.org/stable/c/51f95ea451f25d7e3f048c0f438f04fa74688aae"
        },
        {
          "url": "https://git.kernel.org/stable/c/86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/4fda8f0abeea9929036446d89a476fb8298abcb0"
        },
        {
          "url": "https://git.kernel.org/stable/c/f4845ab191a4f686a5da481fbba90ed73bb693b0"
        }
      ],
      "title": "Bluetooth: hci_core: Serialize ACL scheduling with channel deletion",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98735",
    "datePublished": "2026-10-18T15:47:13.062Z",
    "dateReserved": "2026-09-25T10:25:14.367Z",
    "dateUpdated": "2026-10-30T12:39:11.976Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

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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.
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