CVE-2026-68393 (GCVE-0-2026-68393)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:04 – Updated: 2026-08-17 05:04
VLAI
Title
Bluetooth: hci_sync: extend conn_hash lookup critical sections
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: extend conn_hash lookup critical sections Using RCU-protected pointers outside the critical sections without refcount is incorrect and may result to UAF. Extend critical section to cover both hci_conn_hash lookup and use of the returned conn. Add surrounding rcu_read_lock() also when return value is not used, in preparation for RCU lockdep requirement to hci_lookup_le_connect(). This avoids concurrent deletion of the conn before we are done dereferencing it. Also, make sure to hold hdev->lock when accessing hdev->accept_list.
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 6d0417e4e1cf66fd917f06f0454958362714ef7d , < 83b7e67698d0b93f685875ce82c8d335436834f7 (git)
Affected: 6d0417e4e1cf66fd917f06f0454958362714ef7d , < 38326774df6198df0cc2744cc73bf77cb741c538 (git)
Affected: 6d0417e4e1cf66fd917f06f0454958362714ef7d , < d5efd6e4b8b0634af6843178fe1a7dd2b2178a3d (git)
Affected: eb8b860e87b296bd1874c79a668081efd00f9754 (git)
Affected: 94bf6380e936339a700c0b3171a49baf512aa70b (git)
Affected: 6.12.28 , < 6.13 (semver)
Affected: 6.14.6 , < 6.15 (semver)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
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{
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
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              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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            {
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              "version": "eb8b860e87b296bd1874c79a668081efd00f9754",
              "versionType": "git"
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            {
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              "version": "94bf6380e936339a700c0b3171a49baf512aa70b",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "6.12.28",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "6.14.6",
              "versionType": "semver"
            }
          ]
        },
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          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: extend conn_hash lookup critical sections\n\nUsing RCU-protected pointers outside the critical sections without\nrefcount is incorrect and may result to UAF.\n\nExtend critical section to cover both hci_conn_hash lookup and use of\nthe returned conn.\n\nAdd surrounding rcu_read_lock() also when return value is not used, in\npreparation for RCU lockdep requirement to hci_lookup_le_connect().\n\nThis avoids concurrent deletion of the conn before we are done\ndereferencing it.\n\nAlso, make sure to hold hdev-\u003elock when accessing hdev-\u003eaccept_list."
        }
      ],
      "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 affected code is the Bluetooth HCI sync/scan management layer; both sides of the race are driven by LE radio events (connection complete, disconnect, periodic advertising sync creation/termination) from a device in radio range, requiring no local access.\nAC:L - A nearby attacker drives both sides of the race \u2014 repeated LE connect/disconnect and PA sync setup/teardown queue the hci_sync work while concurrently triggering hci_conn_del() on the event workqueue \u2014 so the window can be re-attempted arbitrarily until won.\nPR:N - The vulnerable hci_update_passive_scan_sync()/hci_update_accept_list_sync()/hci_le_set_ext_scan_param_sync() paths are invoked automatically by the kernel in response to incoming LE connection and periodic-advertising events; the remote attacker needs no credentials or pairing on the target.\nUI:N - No victim action is needed \u2014 background LE scanning and accept-list updates are performed autonomously by the host stack whenever connection state changes.\nS:U - The use-after-free occurs in kernel memory and its impact is confined to the kernel\u0027s own security authority, with no crossing into a separate authorization scope such as a hypervisor or IOMMU boundary.\nC:H - The freed hci_conn is read after release (conn-\u003edst, conn-\u003edst_type, PHY parameters), and a heap-groomed replacement object lets the attacker read attacker-chosen or sensitive kernel data, which can additionally be exfiltrated via the resulting accept-list/scan parameters.\nI:H - hci_conn is kfree()\u0027d via bt_link_release() while still referenced, so reallocating the slab with a controlled object yields write/control-flow primitives typical of slab use-after-free, enabling kernel memory corruption and privilege escalation.\nA:H - Dereferencing the freed hci_conn readily causes slab corruption, KASAN splats, or an oops/panic in the Bluetooth workqueues, taking down the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:04:41.234Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/83b7e67698d0b93f685875ce82c8d335436834f7"
        },
        {
          "url": "https://git.kernel.org/stable/c/38326774df6198df0cc2744cc73bf77cb741c538"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5efd6e4b8b0634af6843178fe1a7dd2b2178a3d"
        }
      ],
      "title": "Bluetooth: hci_sync: extend conn_hash lookup critical sections",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68393",
    "datePublished": "2026-08-10T12:04:12.564Z",
    "dateReserved": "2026-07-30T09:28:09.388Z",
    "dateUpdated": "2026-08-17T05:04:41.234Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-10-03",
      "epss": "0.00375",
      "percentile": "0.29152"
    },
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
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                ],
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                    "versionType": "git"
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                  {
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                    "versionType": "git"
                  },
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                    "status": "affected",
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                    "versionType": "semver"
                  }
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: extend conn_hash lookup critical sections\n\nUsing RCU-protected pointers outside the critical sections without\nrefcount is incorrect and may result to UAF.\n\nExtend critical section to cover both hci_conn_hash lookup and use of\nthe returned conn.\n\nAdd surrounding rcu_read_lock() also when return value is not used, in\npreparation for RCU lockdep requirement to hci_lookup_le_connect().\n\nThis avoids concurrent deletion of the conn before we are done\ndereferencing it.\n\nAlso, make sure to hold hdev-\u003elock when accessing hdev-\u003eaccept_list."
          }
        ],
        "id": "CVE-2026-68393",
        "lastModified": "2026-08-17T06:17:47.983",
        "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"
              },
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
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        },
        "published": "2026-08-10T13:20:32.663",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/38326774df6198df0cc2744cc73bf77cb741c538"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
          {
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T11:24:14+00:00",
      "cve": "CVE-2026-68393",
      "id": "CVE-2026-68393",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "93",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_sync: extend conn_hash lookup critical sections",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68393.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-10-03T00:32:18Z",
      "cve": "CVE-2026-68393",
      "id": "CVE-2026-68393",
      "initial_release_date": "2026-08-13T16:22:34Z",
      "product_status:known_affected": "19",
      "product_status:known_not_affected": "357",
      "product_status:recommended": "145",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68393",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68393.json",
      "version": "5"
    }
  }
}



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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.



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.