{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/l2tp/l2tp_ppp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "78cdfdca88cbf731a92f3b9ee5427c633dd94e28",
              "status": "affected",
              "version": "fd558d186df2c13a22455373858bae634a4795af",
              "versionType": "git"
            },
            {
              "lessThan": "e251d4cdfc725c9e7d686161e3b775a0e7d95053",
              "status": "affected",
              "version": "fd558d186df2c13a22455373858bae634a4795af",
              "versionType": "git"
            },
            {
              "lessThan": "62f327e287cf7b595ae3f73ba72f5cd2a9e9f39f",
              "status": "affected",
              "version": "fd558d186df2c13a22455373858bae634a4795af",
              "versionType": "git"
            },
            {
              "lessThan": "a213a8950414c684999dcf03edeea6c46ede172e",
              "status": "affected",
              "version": "fd558d186df2c13a22455373858bae634a4795af",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/l2tp/l2tp_ppp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.35"
            },
            {
              "lessThan": "2.6.35",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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\nl2tp: pppol2tp: hold reference to session in pppol2tp_ioctl()\n\npppol2tp_ioctl() read sock-\u003esk-\u003esk_user_data directly without any\nlocks or reference counting.  If a controllable sleep was induced during\ncopy_from_user() (e.g. via a userfaultfd page fault sleep), a concurrent\nsocket close could trigger pppol2tp_session_close() asynchronously.  This\nfrees the l2tp_session structure via the l2tp_session_del_work workqueue.\nUpon resuming, the ioctl thread dereferences the stale session pointer,\nresulting in a Use-After-Free (UAF).\n\nFix this by securely fetching the session reference using the RCU-safe,\nrefcounted helper pppol2tp_sock_to_session(sk) on entry.  This locks the\nsession\u0027s refcount across the sleep.  We structured the function to exit\nvia standard err breaks, guaranteeing that l2tp_session_put() is cleanly\ncalled on all return paths to drop the reference.\n\nTo preserve existing behavior we validate the session and its magic\nsignature only for the specific L2TP commands that require it.  This\nensures that generic/unknown ioctls called on an unconnected socket\nstill return -ENOIOCTLCMD and correctly fall back to generic handlers\n(e.g. in sock_do_ioctl())."
    }
  ],
  "id": "CVE-2026-53262",
  "lastModified": "2026-06-30T14:44:27.313",
  "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": "2026-06-25T09:16:44.190",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/62f327e287cf7b595ae3f73ba72f5cd2a9e9f39f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78cdfdca88cbf731a92f3b9ee5427c633dd94e28"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a213a8950414c684999dcf03edeea6c46ede172e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e251d4cdfc725c9e7d686161e3b775a0e7d95053"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

{
  "affected": [],
  "aliases": [
    "CVE-2026-53262"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:44Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: pppol2tp: hold reference to session in pppol2tp_ioctl()\n\npppol2tp_ioctl() read sock-\u003esk-\u003esk_user_data directly without any\nlocks or reference counting.  If a controllable sleep was induced during\ncopy_from_user() (e.g. via a userfaultfd page fault sleep), a concurrent\nsocket close could trigger pppol2tp_session_close() asynchronously.  This\nfrees the l2tp_session structure via the l2tp_session_del_work workqueue.\nUpon resuming, the ioctl thread dereferences the stale session pointer,\nresulting in a Use-After-Free (UAF).\n\nFix this by securely fetching the session reference using the RCU-safe,\nrefcounted helper pppol2tp_sock_to_session(sk) on entry.  This locks the\nsession\u0027s refcount across the sleep.  We structured the function to exit\nvia standard err breaks, guaranteeing that l2tp_session_put() is cleanly\ncalled on all return paths to drop the reference.\n\nTo preserve existing behavior we validate the session and its magic\nsignature only for the specific L2TP commands that require it.  This\nensures that generic/unknown ioctls called on an unconnected socket\nstill return -ENOIOCTLCMD and correctly fall back to generic handlers\n(e.g. in sock_do_ioctl()).",
  "id": "GHSA-5xjr-h8mp-chfc",
  "modified": "2026-06-28T09:31:47Z",
  "published": "2026-06-25T09:31:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53262"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/62f327e287cf7b595ae3f73ba72f5cd2a9e9f39f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78cdfdca88cbf731a92f3b9ee5427c633dd94e28"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a213a8950414c684999dcf03edeea6c46ede172e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e251d4cdfc725c9e7d686161e3b775a0e7d95053"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-53262 l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl() - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-53262.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl()",
    "tracking": {
      "current_release_date": "2026-06-30T15:37:44.000Z",
      "generator": {
        "date": "2026-07-01T07:19:52.386Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-53262",
      "initial_release_date": "2026-06-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-06-27T01:13:52.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-06-28T02:06:20.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        },
        {
          "date": "2026-06-30T15:37:44.000Z",
          "legacy_version": "3",
          "number": "3",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "3"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "azl3 kernel 0:6.6.143.1-1.azl3",
                "product": {
                  "name": "azl3 kernel 0:6.6.143.1-1.azl3",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.143.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-53262",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17084-1"
        ],
        "under_investigation": [
          "17084-2"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-53262 l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl() - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-53262.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-06-27T01:13:52.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-1"
          ]
        }
      ],
      "title": "l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl()"
    }
  ]
}