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GHSA-4PQQ-WHJC-554C

Vulnerability from github – Published: 2026-07-20 18:32 – Updated: 2026-07-20 18:32

Details

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

Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock

l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for pending_rx_work. process_pending_rx() takes the same mutex, so teardown can deadlock against the worker it is flushing.

This issue was found by our static analysis tool and then manually reviewed against the current tree.

The grounded PoC kept the l2cap_conn_ready() -> queue_work(..., &conn->pending_rx_work) submit path, the l2cap_conn_del() -> cancel_work_sync(&conn->pending_rx_work) teardown path, and the process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep

WARNING: possible circular locking dependency detected process_pending_rx+0x21/0x2a [vuln_msv] l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv] *** DEADLOCK ***

Cancel pending_rx_work before taking conn->lock, matching the existing lock-before-drain ordering used for the two delayed works in the same teardown path. The pending_rx queue is still purged after the work has been cancelled and conn->lock has been acquired.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64206"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-20T17:18:22Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock\n\nl2cap_conn_del() takes conn-\u003elock and then calls cancel_work_sync() for\npending_rx_work.  process_pending_rx() takes the same mutex, so teardown\ncan deadlock against the worker it is flushing.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the l2cap_conn_ready() -\u003e queue_work(...,\n\u0026conn-\u003epending_rx_work) submit path, the l2cap_conn_del() -\u003e\ncancel_work_sync(\u0026conn-\u003epending_rx_work) teardown path, and the\nprocess_pending_rx() -\u003e mutex_lock(\u0026conn-\u003elock) worker edge.  Lockdep\n\n  WARNING: possible circular locking dependency detected\n  process_pending_rx+0x21/0x2a [vuln_msv]\n  l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]\n  *** DEADLOCK ***\n\nCancel pending_rx_work before taking conn-\u003elock, matching the existing\nlock-before-drain ordering used for the two delayed works in the same\nteardown path.  The pending_rx queue is still purged after the work has\nbeen cancelled and conn-\u003elock has been acquired.",
  "id": "GHSA-4pqq-whjc-554c",
  "modified": "2026-07-20T18:32:33Z",
  "published": "2026-07-20T18:32:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64206"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2641a9e0a1dd4af2e21995470a21d55dd35e5203"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5616beb3355b5fca2280d796c1cf7ada4ee6551"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e96fbac8d3a73b0bc165383c092a30628561d320"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64206 (GCVE-0-2026-64206)

Vulnerability from cvelistv5 – Published: 2026-07-20 16:27 – Updated: 2026-07-20 16:27

Title

Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for pending_rx_work. process_pending_rx() takes the same mutex, so teardown can deadlock against the worker it is flushing. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the l2cap_conn_ready() -> queue_work(..., &conn->pending_rx_work) submit path, the l2cap_conn_del() -> cancel_work_sync(&conn->pending_rx_work) teardown path, and the process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep WARNING: possible circular locking dependency detected process_pending_rx+0x21/0x2a [vuln_msv] l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv] *** DEADLOCK *** Cancel pending_rx_work before taking conn->lock, matching the existing lock-before-drain ordering used for the two delayed works in the same teardown path. The pending_rx queue is still purged after the work has been cancelled and conn->lock has been acquired.

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/d5616beb3355b5fca…
https://git.kernel.org/stable/c/e96fbac8d3a73b0bc…
https://git.kernel.org/stable/c/2641a9e0a1dd4af2e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < d5616beb3355b5fca2280d796c1cf7ada4ee6551 (git) Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < e96fbac8d3a73b0bc165383c092a30628561d320 (git) Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < 2641a9e0a1dd4af2e21995470a21d55dd35e5203 (git) Affected: ee805f9499ebd0edf0877990968543c752043b59 (git) Affected: 3.15.5 , < 3.16 (semver)
Linux	Linux	Affected: 3.16 Unaffected: 0 , < 3.16 (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d5616beb3355b5fca2280d796c1cf7ada4ee6551",
              "status": "affected",
              "version": "7ab56c3a6eccb215034b0cb096e0313441cbf2a4",
              "versionType": "git"
            },
            {
              "lessThan": "e96fbac8d3a73b0bc165383c092a30628561d320",
              "status": "affected",
              "version": "7ab56c3a6eccb215034b0cb096e0313441cbf2a4",
              "versionType": "git"
            },
            {
              "lessThan": "2641a9e0a1dd4af2e21995470a21d55dd35e5203",
              "status": "affected",
              "version": "7ab56c3a6eccb215034b0cb096e0313441cbf2a4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee805f9499ebd0edf0877990968543c752043b59",
              "versionType": "git"
            },
            {
              "lessThan": "3.16",
              "status": "affected",
              "version": "3.15.5",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.16"
            },
            {
              "lessThan": "3.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "3.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "3.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc3",
                  "versionStartIncluding": "3.16",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "3.15.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock\n\nl2cap_conn_del() takes conn-\u003elock and then calls cancel_work_sync() for\npending_rx_work.  process_pending_rx() takes the same mutex, so teardown\ncan deadlock against the worker it is flushing.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the l2cap_conn_ready() -\u003e queue_work(...,\n\u0026conn-\u003epending_rx_work) submit path, the l2cap_conn_del() -\u003e\ncancel_work_sync(\u0026conn-\u003epending_rx_work) teardown path, and the\nprocess_pending_rx() -\u003e mutex_lock(\u0026conn-\u003elock) worker edge.  Lockdep\n\n  WARNING: possible circular locking dependency detected\n  process_pending_rx+0x21/0x2a [vuln_msv]\n  l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]\n  *** DEADLOCK ***\n\nCancel pending_rx_work before taking conn-\u003elock, matching the existing\nlock-before-drain ordering used for the two delayed works in the same\nteardown path.  The pending_rx queue is still purged after the work has\nbeen cancelled and conn-\u003elock has been acquired."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T16:27:53.885Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d5616beb3355b5fca2280d796c1cf7ada4ee6551"
        },
        {
          "url": "https://git.kernel.org/stable/c/e96fbac8d3a73b0bc165383c092a30628561d320"
        },
        {
          "url": "https://git.kernel.org/stable/c/2641a9e0a1dd4af2e21995470a21d55dd35e5203"
        }
      ],
      "title": "Bluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64206",
    "datePublished": "2026-07-20T16:27:53.885Z",
    "dateReserved": "2026-07-19T15:36:31.769Z",
    "dateUpdated": "2026-07-20T16:27:53.885Z",
    "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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

GHSA-4PQQ-WHJC-554C

CVE-2026-64206 (GCVE-0-2026-64206)

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Sightings

Nomenclature