CVE-2026-74535 (GCVE-0-2026-74535)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:48
VLAI
Title
Bluetooth: ISO: avoid deadlocks in iso_sock_timeout
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: avoid deadlocks in iso_sock_timeout iso_sock_timeout() takes lock_sock, so sync disabling the timer while holding that lock may deadlock. iso_sock_timeout() may also run concurrently with iso_conn_del(), which leads to UAF [Task 1] [Task hdev->workqueue] iso_sock_timeout iso_conn_del iso_conn_hold_unless_zero iso_chan_del `------------> iso_conn_put caller frees hcon iso_conn_put iso_conn_free conn->hcon->iso_data = NULL; /* UAF */ Fix the deadlock by removing the disable from the lock_sock sections. Move the timer from iso_conn to iso_pinfo to decouple it from iso_conn which may need to be freed in lock_sock section. Convert some of the clear_timer to disable_timer.
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: a58d0f5dac322e16cc75334d000666512341bde5 , < 16d89a63e08280abeef7218970a3bbd7ca62b021 (git)
Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < 82e982f54f962f72646868ddbb2c3bd9ea178568 (git)
Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < 3c3d5f85db80145636bb991a6005e2760012b985 (git)
Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < 200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43 (git)
Affected: f53e7489273dc2bb307bf50f319b3762d45534f0 (git)
Affected: 6.12.2 , < 6.12.103 (semver)
Affected: 6.11.11 , < 6.12 (semver)
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Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (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)
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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",
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "git"
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              "version": "f53e7489273dc2bb307bf50f319b3762d45534f0",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "6.12.2",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12",
              "status": "affected",
              "version": "6.11.11",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "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",
              "version": "6.13"
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              "status": "unaffected",
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              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.103",
                  "versionStartIncluding": "6.12.2",
                  "vulnerable": true
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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: avoid deadlocks in iso_sock_timeout\n\niso_sock_timeout() takes lock_sock, so sync disabling the timer while\nholding that lock may deadlock.\n\niso_sock_timeout() may also run concurrently with iso_conn_del(), which\nleads to UAF\n\n        [Task 1]                      [Task hdev-\u003eworkqueue]\n        iso_sock_timeout              iso_conn_del\n          iso_conn_hold_unless_zero     iso_chan_del\n                           `------------\u003e iso_conn_put\n                                      caller frees hcon\n          iso_conn_put\n            iso_conn_free\n              conn-\u003ehcon-\u003eiso_data = NULL; /* UAF */\n\nFix the deadlock by removing the disable from the lock_sock sections.\nMove the timer from iso_conn to iso_pinfo to decouple it from iso_conn\nwhich may need to be freed in lock_sock section. Convert some of the\nclear_timer to disable_timer."
        }
      ],
      "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 socket layer (BTPROTO_ISO); iso_sock_timeout and iso_conn_del are reached via HCI disconnect/connect events from an adjacent BLE peer and local ISO socket syscalls, which per kernel guidance is Adjacent not Network.\nAC:L - Exploitation is a race between iso_sock_timeout and iso_conn_del that an attacker can reliably force by controlling ISO connect/disconnect timing and socket send timeouts (SO_SNDTIMEO) on concurrent workqueues, so success does not depend on uncontrollable conditions.\nPR:N - An adjacent Bluetooth attacker can trigger iso_conn_del through remote HCI disconnect/failure events without any credentials or privileges on the victim host; only a normal active or pending ISO/LE Audio session must exist on the target.\nUI:N - No deliberate victim interaction beyond routine Bluetooth/LE Audio operation is required; exploitation can occur in the background while an ISO connection is pending or active, without opening files or performing a separate enabling action.\nS:U - The UAF/deadlock corrupts kernel heap memory on the host and enables local privilege escalation within the kernel security boundary, not a cross-boundary escape such as VM guest-to-host or IOMMU bypass.\nC:H - iso_conn_free dereferences conn-\u003ehcon after concurrent iso_conn_del frees the hci_conn (UAF on conn-\u003ehcon-\u003eiso_data), enabling arbitrary kernel memory read/disclosure through heap corruption per UAF guidance.\nI:H - The UAF permits writes through conn-\u003ehcon-\u003eiso_data and hci_conn_drop on freed hci_conn memory, providing heap corruption primitives that can be leveraged for arbitrary kernel writes or code execution.\nA:H - The UAF causes kernel oops/panic on freed hci_conn access, and the lock_sock versus disable_delayed_work_sync deadlock in iso_sock_timeout/iso_conn_del paths can hang the system; both crash and deadlock map to High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:24.441Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/16d89a63e08280abeef7218970a3bbd7ca62b021"
        },
        {
          "url": "https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985"
        },
        {
          "url": "https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43"
        }
      ],
      "title": "Bluetooth: ISO: avoid deadlocks in iso_sock_timeout",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74535",
    "datePublished": "2026-08-15T12:27:48.449Z",
    "dateReserved": "2026-08-15T05:44:03.913Z",
    "dateUpdated": "2026-08-17T05:48:24.441Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74535",
      "date": "2026-08-28",
      "epss": "0.00241",
      "percentile": "0.1512"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74535\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T13:17:58.837\",\"lastModified\":\"2026-08-17T06:19:50.587\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: ISO: avoid deadlocks in iso_sock_timeout\\n\\niso_sock_timeout() takes lock_sock, so sync disabling the timer while\\nholding that lock may deadlock.\\n\\niso_sock_timeout() may also run concurrently with iso_conn_del(), which\\nleads to UAF\\n\\n        [Task 1]                      [Task hdev-\u003eworkqueue]\\n        iso_sock_timeout              iso_conn_del\\n          iso_conn_hold_unless_zero     iso_chan_del\\n                           `------------\u003e iso_conn_put\\n                                      caller frees hcon\\n          iso_conn_put\\n            iso_conn_free\\n              conn-\u003ehcon-\u003eiso_data = NULL; /* UAF */\\n\\nFix the deadlock by removing the disable from the lock_sock sections.\\nMove the timer from iso_conn to iso_pinfo to decouple it from iso_conn\\nwhich may need to be freed in lock_sock section. Convert some of the\\nclear_timer to disable_timer.\"}],\"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\":\"a58d0f5dac322e16cc75334d000666512341bde5\",\"lessThan\":\"16d89a63e08280abeef7218970a3bbd7ca62b021\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"dc26097bdb864a0d5955b9a25e43376ffc1af99b\",\"lessThan\":\"82e982f54f962f72646868ddbb2c3bd9ea178568\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"dc26097bdb864a0d5955b9a25e43376ffc1af99b\",\"lessThan\":\"3c3d5f85db80145636bb991a6005e2760012b985\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"dc26097bdb864a0d5955b9a25e43376ffc1af99b\",\"lessThan\":\"200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f53e7489273dc2bb307bf50f319b3762d45534f0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"6.12.2\",\"lessThan\":\"6.12.103\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.11.11\",\"lessThan\":\"6.12\",\"versionType\":\"semver\",\"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\":\"6.13\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.13\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.103\",\"lessThanOrEqual\":\"6.12.*\",\"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/16d89a63e08280abeef7218970a3bbd7ca62b021\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T18:10:24+00:00",
      "cve": "CVE-2026-74535",
      "id": "CVE-2026-74535",
      "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: avoid deadlocks in iso_sock_timeout",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74535.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.