CVE-2026-63975 (GCVE-0-2026-63975)
Vulnerability from cvelistv5
Published
2026-07-19 14:56
Modified
2026-08-05 12:37
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: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp If dcid is received for an already-assigned destination CID the spec requires that both channels to be discarded, but calling l2cap_chan_del may invalidate the tmp cursor created by list_for_each_entry_safe and in fact it is the wrong procedure as the chan->dcid may be assigned previously it really needs to be disconnected. Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so instead schedule l2cap_chan_timeout with delay 0 to close the channel asynchronously.
References
Impacted products
Vendor Product Version
Linux Linux Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
Version: 15f02b91056253e8cdc592888f431da0731337b8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "5.7"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15.210",
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            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
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            },
            {
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              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.259",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
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                  "vulnerable": true
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionEndExcluding": "7.1",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp\n\nIf dcid is received for an already-assigned destination CID the spec\nrequires that both channels to be discarded, but calling l2cap_chan_del\nmay invalidate the tmp cursor created by list_for_each_entry_safe and\nin fact it is the wrong procedure as the chan-\u003edcid may be assigned\npreviously it really needs to be disconnected.\n\nCalling l2cap_chan_clone directly may still lead to l2cap_chan_del so\ninstead schedule l2cap_chan_timeout with delay 0 to close the channel\nasynchronously."
        }
      ],
      "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 reached when a remote Bluetooth LE peer sends a crafted L2CAP_ECRED_CONN_RSP on the LE signaling channel, processed via hci_recv_frame \u2192 l2cap_recv_acldata \u2192 l2cap_le_sig_channel \u2192 l2cap_ecred_conn_rsp. Bluetooth is Adjacent per kernel CVSS guidance.\nAC:L - An adjacent attacker who establishes a BLE ACL link can reliably trigger this by first creating an L2CAP channel with a chosen DCID (via ECRED_CONN_REQ SCIDs) and then sending a connection response reusing that DCID for a pending outgoing ECRED connection; no race or rare layout is required.\nPR:N - Exploitation requires only the ability to act as a remote Bluetooth peer on an established ACL connection; no local shell access, capabilities, or root on the victim system is needed.\nUI:N - The malicious signaling traffic is delivered entirely by the remote attacker once a BLE link exists; no additional victim-side file open, mount, or application action beyond normal Bluetooth connectivity is required to reach the vulnerable handler.\nS:U - The failure is a kernel L2CAP channel-list use-after-free and crash within the Bluetooth stack on the victim host; it does not cross a VM, container, or IOMMU security boundary.\nC:H - Calling l2cap_chan_del() on the original channel during list_for_each_entry_safe can free the saved tmp list node, causing a use-after-free on struct l2cap_chan when iteration continues; UAF is scored as High confidentiality impact.\nI:H - The same iterator invalidation frees and later dereferences l2cap_chan objects under attacker-influenced connection state, providing a heap UAF primitive that can be groomed toward arbitrary memory corruption and code execution.\nA:H - The bug reliably produces kernel list corruption and use-after-free in softirq/context Bluetooth receive path, leading to kernel oops or panic and denial of service on phones, laptops, and embedded devices with Bluetooth enabled."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:46.003Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3c8eaa91eb433c450426539290be4ffe282e9f00"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecfed1e0d8efecad6737a0d83e21d2fd021d8c48"
        },
        {
          "url": "https://git.kernel.org/stable/c/e6833e737a51db1e5ea0401322acf5e22abd8be6"
        },
        {
          "url": "https://git.kernel.org/stable/c/6319b38fe69f56ed95680ade485b957a53fff642"
        },
        {
          "url": "https://git.kernel.org/stable/c/291eec1041c918c460dc9702e44edd17794b4a4b"
        },
        {
          "url": "https://git.kernel.org/stable/c/41e29548b5e8b5e5fcf708786b3bea67cab107fa"
        },
        {
          "url": "https://git.kernel.org/stable/c/d153b8898c0051eb8b6a083b35cbe304a5886bd5"
        },
        {
          "url": "https://git.kernel.org/stable/c/41c2713b204e6cb6a94587bc6bf6935107df5479"
        }
      ],
      "title": "Bluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63975",
    "datePublished": "2026-07-19T14:56:00.662Z",
    "dateReserved": "2026-07-19T07:54:57.024Z",
    "dateUpdated": "2026-08-05T12:37:46.003Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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