CVE-2026-90093 (GCVE-0-2026-90093)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:06 – Updated: 2026-09-18 17:52
VLAI
Title
Bluetooth: L2CAP: access chan->conn safely in get/setsockopt
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: access chan->conn safely in get/setsockopt Since commit b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref") l2cap_chan::conn has held reference and remains non-NULL also after the corresponding hci_conn is deleted. In this state accessing various fields eg. hci_conn::hdev is invalid, which leads to KASAN crash in l2cap_sock_setsockopt() access of conn->hcon->hdev. Check l2cap_chan::conn.hcon corresponds to an alive hci_conn before trying to use it in l2cap_sock.c. Hold l2cap_chan_lock() in getsockopt/setsockopt to ensure it stays alive, and to avoid data races in l2cap_chan fields.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: b66774b48dd98f07254951f74ea6f513efe7ff8b , < f49321c85785178214fd67f2e9b4b73d6363783b (git)
Affected: b66774b48dd98f07254951f74ea6f513efe7ff8b , < ca2c4c26498643f421d35ffe258fafbd3ed461c3 (git)
Affected: 8f90405a4a6f1f1880dc07996b47bf57c712bd8a (git)
Affected: 32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b (git)
Affected: 8922c7940bae9ce4b1736dddb6362370793835c2 (git)
Affected: 91047a4396a8b1857a6f712a90cf33ec0012b189 (git)
Affected: 0b0e2bf39cf99e458d991b9df253727e036a7d7d (git)
Affected: d3b739db5dc6f688a60d56da872fabaf65246032 (git)
Affected: 50c38d9f42a529691e4e67ea9cedf4f0bfc8d277 (git)
Affected: 5.10.265 , < 5.11 (semver)
Affected: 5.15.216 , < 5.16 (semver)
Affected: 6.1.183 , < 6.2 (semver)
Affected: 6.6.145 , < 6.7 (semver)
Affected: 6.12.97 , < 6.13 (semver)
Affected: 6.18.39 , < 6.19 (semver)
Affected: 7.1.4 , < 7.2 (semver)
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Linux Linux Affected: 7.2
Unaffected: 0 , < 7.2 (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_sock.c"
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              "versionType": "semver"
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              "version": "6.1.183",
              "versionType": "semver"
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              "status": "affected",
              "version": "7.1.4",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_sock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "unaffected",
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            },
            {
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.10.265",
                  "vulnerable": true
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                {
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                  "versionStartIncluding": "5.15.216",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.1.183",
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                {
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                  "versionStartIncluding": "6.6.145",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                {
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                  "versionStartIncluding": "7.1.4",
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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: L2CAP: access chan-\u003econn safely in get/setsockopt\n\nSince commit b66774b48dd9 (\"Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref\")\nl2cap_chan::conn has held reference and remains non-NULL also after the\ncorresponding hci_conn is deleted.  In this state accessing various\nfields eg. hci_conn::hdev is invalid, which leads to KASAN crash in\nl2cap_sock_setsockopt() access of conn-\u003ehcon-\u003ehdev.\n\nCheck l2cap_chan::conn.hcon corresponds to an alive hci_conn before\ntrying to use it in l2cap_sock.c.  Hold l2cap_chan_lock() in\ngetsockopt/setsockopt to ensure it stays alive, and to avoid data races\nin l2cap_chan fields."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached from __sys_setsockopt/__sys_getsockopt_iter into l2cap_sock_setsockopt()/l2cap_sock_getsockopt(), which dereference chan-\u003econn-\u003ehcon-\u003ehdev after the HCI device is already gone; the trigger is the local BT_FLUSHABLE/BT_SECURITY/BT_PHY sockopt, not a received L2CAP or HCI PDU. Syzbot frees that hdev via vhci_release()-\u003ehci_unregister_dev(), which an in-range peer cannot invoke.\nAC:L - After b66774b48dd9, l2cap_chan_del() sets FLAG_DEL but leaves chan-\u003econn non-NULL, so a later setsockopt(SOL_BLUETOOTH, BT_FLUSHABLE, BT_FLUSHABLE_OFF) deterministically hits lmp_no_flush_capable(conn-\u003ehcon-\u003ehdev) on the deleted hci_conn. The attacker opens the L2CAP socket, tears down the controller (close of /dev/vhci), then issues the sockopt; no un-controllable race or rare config is required.\nPR:L - l2cap_sock_create() requires capable(CAP_NET_RAW) only for SOCK_RAW; SOCK_SEQPACKET/STREAM/DGRAM L2CAP sockets used here have no capability gate, and vhci_open() likewise has no capable() check. An unprivileged init_net user who can open /dev/vhci (or an equivalent HCI node) can create the socket, unregister the controller, and call setsockopt without real root.\nUI:N - The attacker owns both the AF_BLUETOOTH/BTPROTO_L2CAP fd and the teardown fd: they connect, close /dev/vhci so hci_conn_hash_flush()-\u003el2cap_conn_del() runs, then call setsockopt on their still-open socket. No other user must pair, mount, or click anything.\nS:U - l2cap_sock_setsockopt() is using a dangling hci_dev through l2cap_conn-\u003ehcon after hci_release_dev(); the resulting slab UAF stays inside the host kernel Bluetooth stack and does not cross a VM, IOMMU, or sandbox authority.\nC:H - KASAN reports a use-after-free/OOB read in l2cap_sock_setsockopt() of conn-\u003ehcon-\u003ehdev (lmp_no_flush_capable() reads hdev-\u003efeatures[0][6]; getsockopt BT_SECURITY/BT_PHY and L2CAP_CONNINFO also read hcon fields). The freed hci_dev slab was reused as skbuff_small_head, so spraying that object yields a kernel-memory read primitive through the dangling hdev pointer.\nI:H - The same dangling conn-\u003ehcon remains usable from setsockopt after FLAG_DEL: BT_SECURITY on an ATT socket calls smp_conn_security(conn-\u003ehcon) which touches hcon-\u003ehdev flags and hcon-\u003epending_sec_level, and BT_PHY calls hci_conn_set_phy() on that hcon. A sprayed hci_dev in place of the freed object supplies function pointers (send/reset/workqueues) for write and control-flow hijack.\nA:H - Syzbot crashed in l2cap_sock_setsockopt+0x22c3 (net/bluetooth/l2cap_sock.c:1003) with both KASAN slab-out-of-bounds and use-after-free reads of the released hci_dev after vhci_release()-\u003ehci_release_dev(). Any such UAF dereference oopses or panics the kernel and can be repeated by open/connect/close/setsockopt."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-18T17:52:59.418Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f49321c85785178214fd67f2e9b4b73d6363783b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ca2c4c26498643f421d35ffe258fafbd3ed461c3"
        }
      ],
      "title": "Bluetooth: L2CAP: access chan-\u003econn safely in get/setsockopt",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90093",
    "datePublished": "2026-09-17T16:06:06.843Z",
    "dateReserved": "2026-09-11T19:38:34.786Z",
    "dateUpdated": "2026-09-18T17:52:59.418Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-09-25",
      "epss": "0.00165",
      "percentile": "0.05059"
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    "nvd": {
      "cve": {
        "affected": [
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                    "versionType": "git"
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                    "versionType": "git"
                  },
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                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b",
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                    "version": "d3b739db5dc6f688a60d56da872fabaf65246032",
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                    "version": "50c38d9f42a529691e4e67ea9cedf4f0bfc8d277",
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                ],
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                "versions": [
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                    "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: L2CAP: access chan-\u003econn safely in get/setsockopt\n\nSince commit b66774b48dd9 (\"Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref\")\nl2cap_chan::conn has held reference and remains non-NULL also after the\ncorresponding hci_conn is deleted.  In this state accessing various\nfields eg. hci_conn::hdev is invalid, which leads to KASAN crash in\nl2cap_sock_setsockopt() access of conn-\u003ehcon-\u003ehdev.\n\nCheck l2cap_chan::conn.hcon corresponds to an alive hci_conn before\ntrying to use it in l2cap_sock.c.  Hold l2cap_chan_lock() in\ngetsockopt/setsockopt to ensure it stays alive, and to avoid data races\nin l2cap_chan fields."
          }
        ],
        "id": "CVE-2026-90093",
        "lastModified": "2026-09-18T18:17:41.697",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-17T17:17:00.900",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ca2c4c26498643f421d35ffe258fafbd3ed461c3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f49321c85785178214fd67f2e9b4b73d6363783b"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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