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GHSA-F45G-2GPW-92WG

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-17 06:33

Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: ISO: fix refcounting of iso_conn

iso_conn_del() and iso_chan_del() have a race that results to double-put of iso_conn:

[Task hdev->workqueue]         [Task 2]
iso_conn_del                   iso_chan_del
  iso_conn_hold_unless_zero      iso_conn_lock
  iso_conn_lock                  conn->sk = NULL
                                 iso_conn_unlock
  sk = iso_sock_hold(conn)  <---------´
  if (!sk) iso_conn_put          iso_conn_put
  iso_conn_put /* UAF */

The extra put for !sk in iso_conn_del() is currently required since failing iso_chan_add() may leave iso_conn not associated with any sk.

Fix by having iso_pi(sk)->conn own refcount when non-NULL, so iso_conn_del does not need to put it. Adjust the iso_conn_add() refcounting so that conn is put if it does not get associated with an sk.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74534"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:17:58Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: fix refcounting of iso_conn\n\niso_conn_del() and iso_chan_del() have a race that results to double-put\nof iso_conn:\n\n    [Task hdev-\u003eworkqueue]         [Task 2]\n    iso_conn_del                   iso_chan_del\n      iso_conn_hold_unless_zero      iso_conn_lock\n      iso_conn_lock                  conn-\u003esk = NULL\n                                     iso_conn_unlock\n      sk = iso_sock_hold(conn)  \u003c---------\u00b4\n      if (!sk) iso_conn_put          iso_conn_put\n      iso_conn_put /* UAF */\n\nThe extra put for !sk in iso_conn_del() is currently required since\nfailing iso_chan_add() may leave iso_conn not associated with any sk.\n\nFix by having iso_pi(sk)-\u003econn own refcount when non-NULL, so\niso_conn_del does not need to put it.  Adjust the iso_conn_add()\nrefcounting so that conn is put if it does not get associated with an\nsk.",
  "id": "GHSA-f45g-2gpw-92wg",
  "modified": "2026-08-17T06:33:50Z",
  "published": "2026-08-15T15:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74534"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-74534 (GCVE-0-2026-74534)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:48

Title

Bluetooth: ISO: fix refcounting of iso_conn

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix refcounting of iso_conn iso_conn_del() and iso_chan_del() have a race that results to double-put of iso_conn: [Task hdev->workqueue] [Task 2] iso_conn_del iso_chan_del iso_conn_hold_unless_zero iso_conn_lock iso_conn_lock conn->sk = NULL iso_conn_unlock sk = iso_sock_hold(conn) <---------´ if (!sk) iso_conn_put iso_conn_put iso_conn_put /* UAF */ The extra put for !sk in iso_conn_del() is currently required since failing iso_chan_add() may leave iso_conn not associated with any sk. Fix by having iso_pi(sk)->conn own refcount when non-NULL, so iso_conn_del does not need to put it. Adjust the iso_conn_add() refcounting so that conn is put if it does not get associated with an sk.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/3b921533e8aa95b77…
https://git.kernel.org/stable/c/8208b4939afb0a197…
https://git.kernel.org/stable/c/fdfde532ab1caa165…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < 3b921533e8aa95b77aadcf31737595578e735f3c (git) Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < 8208b4939afb0a1977fffe902c3ca42fe0f3baaa (git) Affected: dc26097bdb864a0d5955b9a25e43376ffc1af99b , < fdfde532ab1caa165fcd8985001157ac8b4db365 (git) Affected: f53e7489273dc2bb307bf50f319b3762d45534f0 (git) Affected: a58d0f5dac322e16cc75334d000666512341bde5 (git) Affected: 6.11.11 , < 6.12 (semver) Affected: 6.12.2 , < 6.13 (semver)
Linux	Linux	Affected: 6.13 Unaffected: 0 , < 6.13 (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": [
            {
              "lessThan": "3b921533e8aa95b77aadcf31737595578e735f3c",
              "status": "affected",
              "version": "dc26097bdb864a0d5955b9a25e43376ffc1af99b",
              "versionType": "git"
            },
            {
              "lessThan": "8208b4939afb0a1977fffe902c3ca42fe0f3baaa",
              "status": "affected",
              "version": "dc26097bdb864a0d5955b9a25e43376ffc1af99b",
              "versionType": "git"
            },
            {
              "lessThan": "fdfde532ab1caa165fcd8985001157ac8b4db365",
              "status": "affected",
              "version": "dc26097bdb864a0d5955b9a25e43376ffc1af99b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f53e7489273dc2bb307bf50f319b3762d45534f0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a58d0f5dac322e16cc75334d000666512341bde5",
              "versionType": "git"
            },
            {
              "lessThan": "6.12",
              "status": "affected",
              "version": "6.11.11",
              "versionType": "semver"
            },
            {
              "lessThan": "6.13",
              "status": "affected",
              "version": "6.12.2",
              "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": [
            {
              "status": "affected",
              "version": "6.13"
            },
            {
              "lessThan": "6.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "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": "6.18.44",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.11.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.12.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: fix refcounting of iso_conn\n\niso_conn_del() and iso_chan_del() have a race that results to double-put\nof iso_conn:\n\n    [Task hdev-\u003eworkqueue]         [Task 2]\n    iso_conn_del                   iso_chan_del\n      iso_conn_hold_unless_zero      iso_conn_lock\n      iso_conn_lock                  conn-\u003esk = NULL\n                                     iso_conn_unlock\n      sk = iso_sock_hold(conn)  \u003c---------\u00b4\n      if (!sk) iso_conn_put          iso_conn_put\n      iso_conn_put /* UAF */\n\nThe extra put for !sk in iso_conn_del() is currently required since\nfailing iso_chan_add() may leave iso_conn not associated with any sk.\n\nFix by having iso_pi(sk)-\u003econn own refcount when non-NULL, so\niso_conn_del does not need to put it.  Adjust the iso_conn_add()\nrefcounting so that conn is put if it does not get associated with an\nsk."
        }
      ],
      "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 Bluetooth ISO connection teardown; a remote LE Audio/CIS/BIS peer in range can trigger iso_conn_del via HCI disconnect events (iso_disconn_cfm) that race with concurrent socket teardown.\nAC:L - The double kref_put race is between iso_conn_del and iso_chan_del; an adjacent attacker controls disconnect timing and can repeatedly connect/disconnect to race automatic kernel and Bluetooth daemon socket cleanup.\nPR:N - No local UNIX privileges are required; a malicious or compromised adjacent Bluetooth ISO peer with an established connection can initiate the disconnect leg without root, capabilities, or user-namespace admin rights.\nUI:N - No explicit victim action is needed beyond an active ISO session; remote disconnect triggers automatic HCI teardown and stack socket close that can race iso_chan_del without the user manually closing applications.\nS:U - The vulnerability corrupts kernel heap lifetime of iso_conn objects within the Bluetooth subsystem and does not cross VM, hypervisor, or IOMMU security boundaries.\nC:H - Premature kfree of iso_conn from the refcount race is a use-after-free that can expose kernel heap contents and be leveraged for arbitrary kernel memory disclosure.\nI:H - UAF on iso_conn enables heap grooming and corrupted pointer dereferences that can be leveraged for arbitrary kernel memory writes or privilege-escalating code execution.\nA:H - The double iso_conn_put can free iso_conn while still referenced, causing kernel oops/panic or reliably exploitable instability during ISO connection teardown."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:23.337Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c"
        },
        {
          "url": "https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa"
        },
        {
          "url": "https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365"
        }
      ],
      "title": "Bluetooth: ISO: fix refcounting of iso_conn",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74534",
    "datePublished": "2026-08-15T12:27:47.831Z",
    "dateReserved": "2026-08-15T05:44:03.913Z",
    "dateUpdated": "2026-08-17T05:48:23.337Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-F45G-2GPW-92WG

CVE-2026-74534 (GCVE-0-2026-74534)

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Sightings

Nomenclature