CVE-2026-74538 (GCVE-0-2026-74538)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:48
VLAI
Title
Bluetooth: ISO: lock sk in iso_connect_ind
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: lock sk in iso_connect_ind Accessing iso_pi(sk)->conn requires lock_sock, which is not taken in the "ev3" part of iso_connect_ind. It may also be NULL if socket has transitioned away from the LISTEN/CONNECT states before locking. Fix by adding lock/release. Recheck hcon is valid after lock acquire where needed.
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: 168d9bf9c7f01df71e6404cfff66d9c2a8e968fb , < e8e9cff6d80eeec28dec4cf7cc18662986945391 (git)
Affected: 168d9bf9c7f01df71e6404cfff66d9c2a8e968fb , < 9bee7e476534f27e830658dad962d85da9edf6bf (git)
Affected: 168d9bf9c7f01df71e6404cfff66d9c2a8e968fb , < 4311fd6f429065a8ba208660360a895627a00cf3 (git)
Affected: 489efc9ae36f164423f5fa7ace772a7ab8131cd8 (git)
Affected: 6.8.9 , < 6.9 (semver)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (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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      "cpeApplicability": [
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              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: lock sk in iso_connect_ind\n\nAccessing iso_pi(sk)-\u003econn requires lock_sock, which is not taken in the\n\"ev3\" part of iso_connect_ind.  It may also be NULL if socket has\ntransitioned away from the LISTEN/CONNECT states before locking.\n\nFix by adding lock/release. Recheck hcon is valid after lock acquire\nwhere needed."
        }
      ],
      "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 hit in hci_le_per_adv_report_evt when the controller delivers HCI_EV_LE_PER_ADV_REPORT from in-range LE periodic advertising; this is the Bluetooth ISO broadcast-sink path on phones/headsets in public spaces, not a local-only syscall entry point.\nAC:L - Exploitation is a socket-lock race where the attacker can repeatedly deliver PA reports and concurrently close or tear down the matching ISO listen socket (or race automatic teardown), controlling both sides rather than depending on uncontrollable memory layout.\nPR:N - An adjacent Bluetooth attacker needs no account or capabilities on the victim; they only need the device to be using LE Audio broadcast reception while they transmit periodic advertising that drives the vulnerable HCI handler.\nUI:N - Once a broadcast sink socket is active, triggering the flaw does not require the victim to perform a specific one-off action at exploit time; the attacker can flood PA reports and race normal stack teardown without user prompts.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security boundary; there is no VM escape, IOMMU bypass, or cross-authority scope change.\nC:H - Missing lock_sock allows TOCTOU/UAF on iso_pi(sk)-\u003econn and stale hci_conn pointers; per kernel guidance, this class of race on connection objects can expose freed kernel heap contents and enable information disclosure primitives.\nI:H - The handler memcpy()s attacker-controlled PA report bytes into hcon-\u003ele_per_adv_data without holding the socket lock, so a stale hcon can turn remote advertising data into an exploitable kernel heap write/control-flow corruption primitive.\nA:H - Concurrent NULL conn dereference or use of a detached hci_conn can oops/panic the kernel during PA reassembly, and the remote PA-report trigger can be repeated to cause sustained denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:26.644Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e8e9cff6d80eeec28dec4cf7cc18662986945391"
        },
        {
          "url": "https://git.kernel.org/stable/c/9bee7e476534f27e830658dad962d85da9edf6bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/4311fd6f429065a8ba208660360a895627a00cf3"
        }
      ],
      "title": "Bluetooth: ISO: lock sk in iso_connect_ind",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74538",
    "datePublished": "2026-08-15T12:27:50.271Z",
    "dateReserved": "2026-08-15T05:44:03.913Z",
    "dateUpdated": "2026-08-17T05:48:26.644Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74538",
      "date": "2026-08-24",
      "epss": "0.00239",
      "percentile": "0.14694"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-17T14:56:00+00:00",
      "cve": "CVE-2026-74538",
      "id": "CVE-2026-74538",
      "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: lock sk in iso_connect_ind",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74538.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-21T00:39:54Z",
      "cve": "CVE-2026-74538",
      "id": "CVE-2026-74538",
      "initial_release_date": "2026-08-15T23:50:46Z",
      "product_status:known_affected": "82",
      "product_status:known_not_affected": "202",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74538",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74538.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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