CVE-2023-53827 (GCVE-0-2023-53827)
Vulnerability from cvelistv5
Published
2025-12-09 01:29
Modified
2026-08-05 09:16
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp} Similar to commit d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put"), just use l2cap_chan_hold_unless_zero to prevent referencing a channel that is about to be destroyed.
Impacted products
Vendor Product Version
Linux Linux Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
Version: 61d6ef3e3408cdf7e622646fb90a9f7f9560b943
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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": [
            {
              "lessThan": "f2d38e77aa5f3effc143e7dd24da8acf02925958",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
              "lessThan": "1351551aa9058e07a20a27a158270cf84fcde621",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
              "lessThan": "c02421992505c95c7f3c9ad59ee35e22eac60988",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
              "lessThan": "d9ba36c22a7bb09d6bac4cc2f243eff05da53f43",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
              "lessThan": "ac6725a634f7e8c0330610a8527f20c730b61115",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            },
            {
              "lessThan": "a2a9339e1c9deb7e1e079e12e27a0265aea8421a",
              "status": "affected",
              "version": "61d6ef3e3408cdf7e622646fb90a9f7f9560b943",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.5"
            },
            {
              "lessThan": "3.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.313",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.281",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.241",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.25",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.2.*",
              "status": "unaffected",
              "version": "6.2.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.14.313",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.19.281",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.241",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.178",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.108",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.25",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.2.12",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3",
                  "versionStartIncluding": "3.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}\n\nSimilar to commit d0be8347c623 (\"Bluetooth: L2CAP: Fix use-after-free\ncaused by l2cap_chan_put\"), just use l2cap_chan_hold_unless_zero to\nprevent referencing a channel that is about to be destroyed."
        }
      ],
      "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 vulnerable code is reached only by processing an L2CAP Disconnect Request/Response signalling PDU received from a Bluetooth peer over a BR/EDR ACL or LE link, which requires the attacker to be within Bluetooth radio range. Per kernel scoring guidance, Bluetooth-reachable code is Adjacent.\nAC:L - The attacker drives both sides: it creates and tears down L2CAP channels at will (CONN_REQ/DISCONN_REQ, ECRED reconfigure responses that call l2cap_chan_del with no lock) while flooding disconnect signalling to hit the window where the kref has reached zero but the channel is still on conn-\u003echan_l, and can retry the connect/disconnect cycle indefinitely at no cost. syzbot reproduced the identical pattern in the sibling handler.\nPR:N - l2cap_recv_frame dispatches CID 0x0001/0x0005 straight to the signalling handlers with no security-level, pairing, or encryption check, so an entirely unauthenticated, unpaired in-range device can send the triggering PDU. Fixed channels present on conn-\u003echan_l give a valid target CID without any local socket.\nUI:N - No victim action is needed \u2014 the packet is processed by hci_rx_work as soon as it arrives on a connectable/advertising host with Bluetooth enabled, which is the default on phones, cars, headsets and laptops.\nS:U - The corruption and its consequences are confined to the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The handler reads chan-\u003escid and chan-\u003edcid out of the freed kmalloc-1k object and echoes them to the attacker in the Disconnect Response, giving a repeatable remote leak of reclaimed kernel heap contents, and the broader use-after-free permits arbitrary read via heap grooming.\nI:H - After the increment-on-zero the code performs three indirect calls (chan-\u003eops-\u003eset_shutdown, -\u003eteardown, -\u003eclose) through function pointers read from the freed object plus a list_del on freed list heads, so an attacker who sprays the reclaimed kmalloc-1024 slot obtains control-flow hijack and arbitrary-write primitives.\nA:H - The bug is a KASAN-confirmed use-after-free that mutex_locks freed memory and triggers a refcount_t \"increment on 0\" splat, reliably producing a kernel oops/panic, and it can be re-triggered remotely at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:16:16.899Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f2d38e77aa5f3effc143e7dd24da8acf02925958"
        },
        {
          "url": "https://git.kernel.org/stable/c/1351551aa9058e07a20a27a158270cf84fcde621"
        },
        {
          "url": "https://git.kernel.org/stable/c/c02421992505c95c7f3c9ad59ee35e22eac60988"
        },
        {
          "url": "https://git.kernel.org/stable/c/d9ba36c22a7bb09d6bac4cc2f243eff05da53f43"
        },
        {
          "url": "https://git.kernel.org/stable/c/ac6725a634f7e8c0330610a8527f20c730b61115"
        },
        {
          "url": "https://git.kernel.org/stable/c/348d446762e7c70778df8bafbdf3fa0df2123f58"
        },
        {
          "url": "https://git.kernel.org/stable/c/d82a439c3cfdb28aa7e82e2e849c5c4dd9fca284"
        },
        {
          "url": "https://git.kernel.org/stable/c/a2a9339e1c9deb7e1e079e12e27a0265aea8421a"
        }
      ],
      "title": "Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53827",
    "datePublished": "2025-12-09T01:29:40.794Z",
    "dateReserved": "2025-12-09T01:27:17.825Z",
    "dateUpdated": "2026-08-05T09:16:16.899Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
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