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CVE-2026-74537 (GCVE-0-2026-74537)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:48
VLAI
Title
Bluetooth: ISO: hold sk properly in iso_conn_ready
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: hold sk properly in iso_conn_ready sk deref in iso_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk is currently accessed without either: [Task 1] [Task 2] iso_sock_release iso_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) iso_sock_kill(sk) UAF on sk deref Fix possible UAF by holding sk refcount in iso_conn_ready(). Also recheck after lock_sock that the socket is still valid. Adjust locking so conn->sk is cleared only under lock_sock.
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: 27c24fda62b601d6f9ca5e992502578c4310876f , < 4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5 (git)
Affected: 27c24fda62b601d6f9ca5e992502578c4310876f , < 1308d72903d792d10b82bc4ef08b8a4452308b04 (git)
Affected: 27c24fda62b601d6f9ca5e992502578c4310876f , < 0d255e63fcf3f13a570d7ac11678fa1164ac015c (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/iso.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "version": "5.15"
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              "status": "unaffected",
              "version": "0",
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              "versionType": "semver"
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              "version": "7.1.8",
              "versionType": "semver"
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        {
          "nodes": [
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                  "versionStartIncluding": "5.15",
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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: ISO: hold sk properly in iso_conn_ready\n\nsk deref in iso_conn_ready must be done either under conn-\u003elock, or\nholding a refcount, to avoid concurrent close. conn-\u003esk is currently\naccessed without either:\n\n    [Task 1]            [Task 2]\n                        iso_sock_release\n    iso_conn_ready\n      sk = conn-\u003esk\n                          lock_sock(sk)\n                            conn-\u003esk = NULL\n      lock_sock(sk)\n                          release_sock(sk)\n                          iso_sock_kill(sk)\n       UAF on sk deref\n\nFix possible UAF by holding sk refcount in iso_conn_ready().  Also\nrecheck after lock_sock that the socket is still valid.  Adjust locking\nso conn-\u003esk is cleared only under lock_sock."
        }
      ],
      "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 bug is in the Bluetooth ISO stack; iso_conn_ready runs from HCI connection-confirmation events (CIS/BIS/PA sync) driven by LE isochronous traffic from Bluetooth peers within radio range, which is an adjacent attack surface (phones, earbuds, automotive, embedded).\nAC:L - This is a use-after-free race between iso_conn_ready and iso_sock_release/iso_sock_kill; an attacker who controls both an ISO socket close and concurrent HCI completion (e.g., dual-thread connect/close or rapid adjacent CIS/BIS establish-teardown) can reliably trigger it without uncontrollable conditions.\nPR:N - Exploitation requires no elevated credentials on the victim: HCI events are processed for any Bluetooth-enabled device in range, and the racing socket close can occur from automatic stack/daemon teardown during connection setup without the victim performing privileged local actions.\nUI:N - No victim interaction is required when the OS Bluetooth stack (e.g., LE Audio on Android phones or bluetoothd on Linux) automatically manages ISO sockets during pairing, reconnection, or broadcast sync while processing peer-initiated CIS/BIS traffic.\nS:U - The UAF corrupts kernel socket memory and can enable local privilege escalation within the kernel; it does not cross a VM, container, or IOMMU security boundary, so scope remains unchanged.\nC:H - Use-after-free on struct sock after iso_sock_kill frees the socket lets an attacker dereference attacker-influenced freed heap memory, enabling arbitrary kernel memory disclosure via heap grooming and reuse of the sock object.\nI:H - The UAF touches sk-\u003esk_state and sk-\u003esk_state_change during iso_sock_ready on a freed sock, providing a standard kernel heap corruption primitive that can be leveraged for arbitrary write and control-flow hijack.\nA:H - Concurrent iso_sock_kill and iso_conn_ready can dereference freed socket memory, causing kernel oops/panic from invalid lock_sock/sk_state access; UAF in the Bluetooth ISO path is inherently a high-availability risk even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:25.530Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5"
        },
        {
          "url": "https://git.kernel.org/stable/c/1308d72903d792d10b82bc4ef08b8a4452308b04"
        },
        {
          "url": "https://git.kernel.org/stable/c/0d255e63fcf3f13a570d7ac11678fa1164ac015c"
        }
      ],
      "title": "Bluetooth: ISO: hold sk properly in iso_conn_ready",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74537",
    "datePublished": "2026-08-15T12:27:49.668Z",
    "dateReserved": "2026-08-15T05:44:03.913Z",
    "dateUpdated": "2026-08-17T05:48:25.530Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74537",
      "date": "2026-09-04",
      "epss": "0.00239",
      "percentile": "0.14816"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-23T15:01:41.000Z",
      "cve": "CVE-2026-74537",
      "id": "msrc_CVE-2026-74537",
      "initial_release_date": "2026-08-23T15:01:41.000Z",
      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: ISO: hold sk properly in iso_conn_ready",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74537.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74537\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T13:17:59.040\",\"lastModified\":\"2026-08-17T06:19:50.807\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: ISO: hold sk properly in iso_conn_ready\\n\\nsk deref in iso_conn_ready must be done either under conn-\u003elock, or\\nholding a refcount, to avoid concurrent close. conn-\u003esk is currently\\naccessed without either:\\n\\n    [Task 1]            [Task 2]\\n                        iso_sock_release\\n    iso_conn_ready\\n      sk = conn-\u003esk\\n                          lock_sock(sk)\\n                            conn-\u003esk = NULL\\n      lock_sock(sk)\\n                          release_sock(sk)\\n                          iso_sock_kill(sk)\\n       UAF on sk deref\\n\\nFix possible UAF by holding sk refcount in iso_conn_ready().  Also\\nrecheck after lock_sock that the socket is still valid.  Adjust locking\\nso conn-\u003esk is cleared only under lock_sock.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/bluetooth/iso.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"27c24fda62b601d6f9ca5e992502578c4310876f\",\"lessThan\":\"4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"27c24fda62b601d6f9ca5e992502578c4310876f\",\"lessThan\":\"1308d72903d792d10b82bc4ef08b8a4452308b04\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"27c24fda62b601d6f9ca5e992502578c4310876f\",\"lessThan\":\"0d255e63fcf3f13a570d7ac11678fa1164ac015c\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/bluetooth/iso.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.15\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.15\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.44\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.8\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"ADJACENT_NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0d255e63fcf3f13a570d7ac11678fa1164ac015c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1308d72903d792d10b82bc4ef08b8a4452308b04\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4e9b5e8669b3602a4e01b6d1e9539b72e42c84d5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-21T08:20:56+00:00",
      "cve": "CVE-2026-74537",
      "id": "CVE-2026-74537",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: ISO: hold sk properly in iso_conn_ready",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74537.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.

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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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