Vulnerability-Lookup

FKIE_CVE-2026-74530

Vulnerability from fkie_nvd - Published: 2026-08-15 13:17 - Updated: 2026-08-17 06:19

Severity

8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback There is theoretical UAF if the conn is freed while the hci_sync task is running. Hold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to match the previous behavior.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2d91e6244b69d752503b2d44020d8b0e323dbd38",
              "status": "affected",
              "version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
              "versionType": "git"
            },
            {
              "lessThan": "56e78b670356caab0b607e8aad4cf819a1909d07",
              "status": "affected",
              "version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "620810ac1f7f1133a9ac403e132b3ad6995ddf39",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee0586ad64a805eaf1a9a10100e908627a561e34",
              "versionType": "git"
            },
            {
              "lessThan": "6.13",
              "status": "affected",
              "version": "6.12.28",
              "versionType": "semver"
            },
            {
              "lessThan": "6.15",
              "status": "affected",
              "version": "6.14.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior."
    }
  ],
  "id": "CVE-2026-74530",
  "lastModified": "2026-08-17T06:19:49.880",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T13:17:58.297",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-74530 (GCVE-0-2026-74530)

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

Title

Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback

Summary

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

2 references

URL	Tags
https://git.kernel.org/stable/c/2d91e6244b69d7525…
https://git.kernel.org/stable/c/56e78b670356caab0…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 024421cf39923927ab2b5fe895d1d922b9abe67f , < 2d91e6244b69d752503b2d44020d8b0e323dbd38 (git) Affected: 024421cf39923927ab2b5fe895d1d922b9abe67f , < 56e78b670356caab0b607e8aad4cf819a1909d07 (git) Affected: 620810ac1f7f1133a9ac403e132b3ad6995ddf39 (git) Affected: ee0586ad64a805eaf1a9a10100e908627a561e34 (git) Affected: 6.12.28 , < 6.13 (semver) Affected: 6.14.6 , < 6.15 (semver)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (semver) Unaffected: 7.1.8 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2d91e6244b69d752503b2d44020d8b0e323dbd38",
              "status": "affected",
              "version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
              "versionType": "git"
            },
            {
              "lessThan": "56e78b670356caab0b607e8aad4cf819a1909d07",
              "status": "affected",
              "version": "024421cf39923927ab2b5fe895d1d922b9abe67f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "620810ac1f7f1133a9ac403e132b3ad6995ddf39",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ee0586ad64a805eaf1a9a10100e908627a561e34",
              "versionType": "git"
            },
            {
              "lessThan": "6.13",
              "status": "affected",
              "version": "6.12.28",
              "versionType": "semver"
            },
            {
              "lessThan": "6.15",
              "status": "affected",
              "version": "6.14.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "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": "7.1.8",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.12.28",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.14.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior."
        }
      ],
      "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 LE ISO BIG Create Sync handling (hci_connect_big_sync), reachable via adjacent BLE traffic that drives HCI events (e.g. HCI_EVT_LE_BIG_INFO_ADV_REPORT through iso_connect_ind) and via local ISO sockets; Bluetooth kernel bugs are scored as Adjacent, not Network.\nAC:L - After 024421cf3992 the path blocks in __hci_cmd_sync_status_sk for up to conn_timeout while only holding a bare hci_conn pointer; an attacker who can open/close an ISO broadcast socket (or race teardown during that wait) controls both sides of the race and can reliably trigger the UAF.\nPR:N - Exploitation does not require root or CAP_NET_ADMIN; adjacent attackers can trigger the vulnerable code through unauthenticated over-the-air BLE broadcasts processed by the kernel HCI layer, and local exploitation only needs standard Bluetooth/ISO socket access available to unprivileged users/apps with Bluetooth permission.\nUI:N - No victim interaction is required beyond attacker-controlled actions such as creating an ISO broadcast listener socket, starting BIG sync, and concurrently closing the socket to free hci_conn while hci_sync work is still running; exploitation does not depend on another user opening files or mounting resources.\nS:U - The use-after-free corrupts kernel heap memory within the Bluetooth/hci_conn subsystem and can lead to local privilege escalation, but it does not cross a VM, IOMMU, or sandbox security boundary into another authority domain.\nC:H - This is a kernel heap use-after-free of struct hci_conn; freed connection objects can be reallocated and read through subsequent dereferences in create_big_complete and hci_le_big_create_sync, providing a standard path to arbitrary kernel memory disclosure.\nI:H - UAF on struct hci_conn allows corrupting connection flags and adjacent heap contents; the structure contains function pointers (cleanup, connect_cfm_cb, disconn_cfm_cb) and is large enough to support heap grooming toward arbitrary write or control-flow hijack.\nA:H - Use-after-free during clear_bit on conn-\u003eflags in create_big_complete, or accessing conn fields after teardown during the blocking BIG sync command, can cause kernel oops/panic and repeated disruption; UAF availability impact is rated High per kernel guidance."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:20.035Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38"
        },
        {
          "url": "https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07"
        }
      ],
      "title": "Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74530",
    "datePublished": "2026-08-15T12:27:45.381Z",
    "dateReserved": "2026-08-15T05:44:03.912Z",
    "dateUpdated": "2026-08-17T05:48:20.035Z",
    "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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FKIE_CVE-2026-74530

CVE-2026-74530 (GCVE-0-2026-74530)

Tags

Sightings

Nomenclature