FKIE_CVE-2026-74540

Vulnerability from fkie_nvd - Published: 2026-08-15 13:17 - Updated: 2026-08-19 17:21
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 UAF in l2cap_le_connect_rsp l2cap_le_connect_rsp() obtains a channel via __l2cap_get_chan_by_ident() but neither holds a reference nor uses l2cap_chan_hold_unless_zero() before locking and operating on it. A concurrent l2cap_chan_del() triggered by a remote disconnect can free the channel between the lookup and l2cap_chan_lock(), causing a use-after-free. The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero() to safely hold a reference, but l2cap_le_connect_rsp() was left unprotected. Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup and l2cap_chan_put() on the exit path, consistent with other L2CAP response handlers.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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": "15d6c2367217a6a20b1abae9f38ded716bf620f1",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "1818180fe12d6cec7a437bc59cde8efdf6b10250",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "8325eafb38c3dee5af329266393763693d17381b",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "fd4c1e301bdec60a40728ea37de531cbccda501a",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "522b730c62c53a1981604fd73524697fd347830d",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "09f447accc2570751e7d17f0dc0788b40d3edade",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "versionType": "git"
            },
            {
              "lessThan": "c4740e7f23ff9a8210198d8b4703259e21b9f69d",
              "status": "affected",
              "version": "f1496dee9cbde2a62821f4441dadb0d3360f60c3",
              "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": "3.14"
            },
            {
              "lessThan": "3.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.103",
              "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"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp\n\nl2cap_le_connect_rsp() obtains a channel via\n__l2cap_get_chan_by_ident() but neither holds a reference nor uses\nl2cap_chan_hold_unless_zero() before locking and operating on it.\nA concurrent l2cap_chan_del() triggered by a remote disconnect can\nfree the channel between the lookup and l2cap_chan_lock(), causing\na use-after-free.\n\nThe BR/EDR counterpart l2cap_connect_rsp() and the sibling handler\nl2cap_le_command_rej() already use l2cap_chan_hold_unless_zero()\nto safely hold a reference, but l2cap_le_connect_rsp() was left\nunprotected.\n\nFix by adding l2cap_chan_hold_unless_zero() after the ident lookup\nand l2cap_chan_put() on the exit path, consistent with other L2CAP\nresponse handlers."
    }
  ],
  "id": "CVE-2026-74540",
  "lastModified": "2026-08-19T17:21:09.300",
  "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": "2026-08-15T13:17:59.337",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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