CVE-2026-74531 (GCVE-0-2026-74531)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-23 12:47
VLAI
Title
Bluetooth: hci_conn: hold conn reference in abort_conn_sync()
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: hold conn reference in abort_conn_sync() There is theoretical UAF if the conn is freed while the hci_sync task is running. Hold refcount to avoid that.
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 CPE status
Linux Linux Affected: 249c88e7fb45b6b705040c5af4bd0d0f2bc9735c , < 64d1645f26aa49b5a86ba2fccd0bb6749ea725a6 (git)
Affected: 227a0cdf4a028a73dc256d0f5144b4808d718893 , < 963fb4b8e7d1ab07b4ae45bf15d41e667c88caca (git)
Affected: 227a0cdf4a028a73dc256d0f5144b4808d718893 , < e8f9fef362bab431d95371d3406bc720350290c3 (git)
Affected: 227a0cdf4a028a73dc256d0f5144b4808d718893 , < fa812cfa81aa3d4a7b6ce8277979af57b3f79712 (git)
Affected: 227a0cdf4a028a73dc256d0f5144b4808d718893 , < 5761d003daa987ac81463f570713ce9c9dd204e5 (git)
Affected: 7fe4d391e937c2f048a43ff4b421e677f10d83c0 (git)
Affected: 58afdc9b18871eb1d461c725be9e9f3f44a39aeb (git)
Affected: 6.6.51 , < 6.6.151 (semver)
Affected: 6.1.184 , < 6.2 (semver)
Affected: 6.10.10 , < 6.11 (semver)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.6.151 , ≤ 6.6.* (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
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        {
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          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
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              "versionType": "semver"
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              "version": "7.1.8",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: hold conn reference in abort_conn_sync()\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that."
        }
      ],
      "metrics": [
        {
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            "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"
          },
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            {
              "lang": "en",
              "value": "AV:A - The flaw is in the Bluetooth HCI connection abort path reachable when a nearby attacker sends connection, authentication-failure, or disconnect traffic that drives hci_disconnect()/hci_abort_conn() through hci_event processing.\nAC:L - An adjacent attacker can repeatedly initiate, fail, and tear down connections to race asynchronous abort_conn_sync work against hci_conn_del(), controlling both sides of the timing window without depending on uncontrollable system state.\nPR:N - Exploitation requires no local account or kernel privileges; a remote Bluetooth peer within RF range can trigger hci_abort_conn() via standard HCI event handling without authenticated pairing or CAP_NET_ADMIN access.\nUI:N - No deliberate victim action beyond normal Bluetooth availability is required; exploitation works against discoverable/connectable devices and already-paired reconnections without opening files or confirming a one-off prompt.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the host kernel security boundary, not a cross-boundary escape such as VM guest-to-host or IOMMU bypass.\nC:H - Use-after-free of struct hci_conn lets an attacker read freed slab memory through abort_conn_sync/hci_abort_conn_sync field accesses, enabling disclosure of kernel pointers and adjacent heap contents.\nI:H - UAF of hci_conn is heap memory corruption that can be shaped via slab reuse and exploited for arbitrary kernel writes or control-flow hijack, not merely a bounded data change.\nA:H - Accessing a freed hci_conn during abort_conn_sync can cause kernel oops, BUG, or panic, and UAF corruption can crash or hang the system even when full exploitation is not attempted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-23T12:47:34.295Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/5761d003daa987ac81463f570713ce9c9dd204e5"
        }
      ],
      "title": "Bluetooth: hci_conn: hold conn reference in abort_conn_sync()",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74531",
    "datePublished": "2026-08-15T12:27:45.988Z",
    "dateReserved": "2026-08-15T05:44:03.912Z",
    "dateUpdated": "2026-08-23T12:47:34.295Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-08-28",
      "epss": "0.00254",
      "percentile": "0.16639"
    },
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      "cve": "CVE-2026-74531",
      "id": "msrc_CVE-2026-74531",
      "initial_release_date": "2026-08-23T14:45:07.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: hci_conn: hold conn reference in abort_conn_sync()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74531.json",
      "version": "1"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-21T07:12:02+00:00",
      "cve": "CVE-2026-74531",
      "id": "CVE-2026-74531",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_conn: hold conn reference in abort_conn_sync()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74531.json",
      "version": "3"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.