{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "nltk",
        "resource_purl": "pkg:pypi/nltk@3.10.3",
        "upstream_fixed_in": "3.10.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "acronym",
        "purl": "pkg:brew/acronym"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.0.0_4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/nltk@3.10.3",
        "name": "nltk",
        "resource": "nltk",
        "strategy": "registry",
        "subject_version": "3.10.3"
      }
    ]
  },
  "details": "### Summary\n\nThere\u0027s a logic bug in `FileSystemPathPointer.open()` inside `nltk/data.py`\nthat makes the sandbox check permanently inert. The guard condition is always\n`False` \u2014 meaning any file the process can read is accessible by passing a\n`file://` URL to `nltk.data.load()`.\n\n---\n\n### Details\n\nIn `nltk/data.py`, `FileSystemPathPointer.open()` was patched at some point\nwith a comment saying \"SECURITY PATCH ENFORCING SANDBOX\", but the check\ndoesn\u0027t work:\n```python\ndef open(self, encoding=None):\n    path = os.path.normpath(self._path)\n\n    # Block raw absolute reads such as \"/\" \"C:\\\\Windows\" etc.\n    if os.path.isabs(path) and path != os.path.normpath(self._path):\n        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n\n    stream = open(self._path, \"rb\")\n```\n\n`path` is set to `os.path.normpath(self._path)` on line 1, then compared\nagainst `os.path.normpath(self._path)` again in the condition. They are\nalways equal. The `ValueError` never fires.\n\nOn top of that, `__init__` already calls `os.path.abspath()` before storing\n`self._path`, so it\u0027s normalized before `open()` is even called. Running\n`normpath` on it again changes nothing.\n\nThe `stream = open(self._path, \"rb\")` line is always reached regardless of\nwhat path was passed in.\n\n---\n\n### PoC\n\nTested on Python 3.11, NLTK 3.9.1, Ubuntu 22.04.\n```python\nimport nltk\nfrom nltk.data import FileSystemPathPointer\n\n# direct construction\nptr = FileSystemPathPointer(\"/etc/passwd\")\nwith ptr.open() as f:\n    print(f.read(300))\n\n# via load() using file:// URL\ndata = nltk.data.load(\"file:///etc/passwd\", format=\"raw\")\nprint(data[:300])\n```\n\nBoth print file contents. No exception is raised.\n\n---\n\n### Impact\n\nAny app that lets users influence the string passed to `nltk.data.load()` or\n`nltk.data.find()` is exposed \u2014 web APIs, notebook servers, multi-tenant\npipelines. An attacker can read any file the process user has access to:\n`/etc/passwd`, `.env` files, private keys, `~/.aws/credentials`, etc.\n\n## Suggested Fix\n\n**File:** `nltk/data.py` \u2014 `FileSystemPathPointer.open()` (lines 378\u2013390)\n\n### What\u0027s wrong\n\nLine 387 compares `normpath(self._path)` against itself \u2014 always equal,\nso the `ValueError` never fires. The check is dead code.\n`__init__` already calls `abspath()` on construction, so re-running\n`normpath` inside `open()` changes nothing either.\n\n---\n\n### Fix\n\nValidate against the actual list of permitted data directories instead:\n```python\ndef open(self, encoding=None):\n    import nltk.data as _d\n    allowed = [os.path.abspath(p) for p in _d.path if p]\n    if allowed and not any(\n        os.path.commonpath([self._path, r]) == r for r in allowed\n    ):\n        raise ValueError(\n            f\"Access outside nltk_data blocked: {self._path!r}\"\n        )\n    stream = open(self._path, \"rb\")\n    if encoding is not None:\n        stream = SeekableUnicodeStreamReader(stream, encoding)\n    return stream\n```\n\n---\n\n### Why `commonpath` not `startswith`\n\n`startswith` is bypassable by a path that shares a prefix:\n```\n/tmp/nltk_data_evil\".startswith(\"/tmp/nltk_data\") \u2192 True  \u2717\ncommonpath([\"/tmp/nltk_data_evil\", \"/tmp/nltk_data\"]) \u2192 \"/tmp\"  \u2713\n```\n\n---\n\n### Diff\n```diff\n-    path = os.path.normpath(self._path)\n-    if os.path.isabs(path) and path != os.path.normpath(self._path):\n-        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n-\n+    import nltk.data as _d\n+    allowed = [os.path.abspath(p) for p in _d.path if p]\n+    if allowed and not any(\n+        os.path.commonpath([self._path, r]) == r for r in allowed\n+    ):\n+        raise ValueError(f\"Access outside nltk_data blocked: {self._path!r}\")\n     stream = open(self._path, \"rb\")\n```",
  "id": "BREW-acronym-CVE-2026-65915",
  "modified": "2026-09-17T18:47:55Z",
  "published": "2026-09-02T08:43:54Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65915"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/pull/3522"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/commit/69db9911fdba914ceeaca7aec6e892d1b14586a9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nltk/nltk"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3731.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/a510de7b-ffaf-4a83-9bf8-fa7e63f4bd2d"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NLTK: FileSystemPathPointer.open() sandbox check is dead code \u2014 arbitrary file read via file:// protocol",
  "upstream": [
    "PYSEC-2026-3731",
    "CVE-2026-65915",
    "GHSA-72r2-7mfr-5xr9"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "nltk",
        "resource_purl": "pkg:pypi/nltk@3.10.3",
        "upstream_fixed_in": "3.10.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "gptline",
        "purl": "pkg:brew/gptline"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.0.8"
            },
            {
              "fixed": "1.0.8_22"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/nltk@3.10.3",
        "name": "nltk",
        "resource": "nltk",
        "strategy": "registry",
        "subject_version": "3.10.3"
      }
    ]
  },
  "details": "### Summary\n\nThere\u0027s a logic bug in `FileSystemPathPointer.open()` inside `nltk/data.py`\nthat makes the sandbox check permanently inert. The guard condition is always\n`False` \u2014 meaning any file the process can read is accessible by passing a\n`file://` URL to `nltk.data.load()`.\n\n---\n\n### Details\n\nIn `nltk/data.py`, `FileSystemPathPointer.open()` was patched at some point\nwith a comment saying \"SECURITY PATCH ENFORCING SANDBOX\", but the check\ndoesn\u0027t work:\n```python\ndef open(self, encoding=None):\n    path = os.path.normpath(self._path)\n\n    # Block raw absolute reads such as \"/\" \"C:\\\\Windows\" etc.\n    if os.path.isabs(path) and path != os.path.normpath(self._path):\n        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n\n    stream = open(self._path, \"rb\")\n```\n\n`path` is set to `os.path.normpath(self._path)` on line 1, then compared\nagainst `os.path.normpath(self._path)` again in the condition. They are\nalways equal. The `ValueError` never fires.\n\nOn top of that, `__init__` already calls `os.path.abspath()` before storing\n`self._path`, so it\u0027s normalized before `open()` is even called. Running\n`normpath` on it again changes nothing.\n\nThe `stream = open(self._path, \"rb\")` line is always reached regardless of\nwhat path was passed in.\n\n---\n\n### PoC\n\nTested on Python 3.11, NLTK 3.9.1, Ubuntu 22.04.\n```python\nimport nltk\nfrom nltk.data import FileSystemPathPointer\n\n# direct construction\nptr = FileSystemPathPointer(\"/etc/passwd\")\nwith ptr.open() as f:\n    print(f.read(300))\n\n# via load() using file:// URL\ndata = nltk.data.load(\"file:///etc/passwd\", format=\"raw\")\nprint(data[:300])\n```\n\nBoth print file contents. No exception is raised.\n\n---\n\n### Impact\n\nAny app that lets users influence the string passed to `nltk.data.load()` or\n`nltk.data.find()` is exposed \u2014 web APIs, notebook servers, multi-tenant\npipelines. An attacker can read any file the process user has access to:\n`/etc/passwd`, `.env` files, private keys, `~/.aws/credentials`, etc.\n\n## Suggested Fix\n\n**File:** `nltk/data.py` \u2014 `FileSystemPathPointer.open()` (lines 378\u2013390)\n\n### What\u0027s wrong\n\nLine 387 compares `normpath(self._path)` against itself \u2014 always equal,\nso the `ValueError` never fires. The check is dead code.\n`__init__` already calls `abspath()` on construction, so re-running\n`normpath` inside `open()` changes nothing either.\n\n---\n\n### Fix\n\nValidate against the actual list of permitted data directories instead:\n```python\ndef open(self, encoding=None):\n    import nltk.data as _d\n    allowed = [os.path.abspath(p) for p in _d.path if p]\n    if allowed and not any(\n        os.path.commonpath([self._path, r]) == r for r in allowed\n    ):\n        raise ValueError(\n            f\"Access outside nltk_data blocked: {self._path!r}\"\n        )\n    stream = open(self._path, \"rb\")\n    if encoding is not None:\n        stream = SeekableUnicodeStreamReader(stream, encoding)\n    return stream\n```\n\n---\n\n### Why `commonpath` not `startswith`\n\n`startswith` is bypassable by a path that shares a prefix:\n```\n/tmp/nltk_data_evil\".startswith(\"/tmp/nltk_data\") \u2192 True  \u2717\ncommonpath([\"/tmp/nltk_data_evil\", \"/tmp/nltk_data\"]) \u2192 \"/tmp\"  \u2713\n```\n\n---\n\n### Diff\n```diff\n-    path = os.path.normpath(self._path)\n-    if os.path.isabs(path) and path != os.path.normpath(self._path):\n-        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n-\n+    import nltk.data as _d\n+    allowed = [os.path.abspath(p) for p in _d.path if p]\n+    if allowed and not any(\n+        os.path.commonpath([self._path, r]) == r for r in allowed\n+    ):\n+        raise ValueError(f\"Access outside nltk_data blocked: {self._path!r}\")\n     stream = open(self._path, \"rb\")\n```",
  "id": "BREW-gptline-CVE-2026-65915",
  "modified": "2026-09-17T19:32:01Z",
  "published": "2026-09-02T09:04:32Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65915"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/pull/3522"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/commit/69db9911fdba914ceeaca7aec6e892d1b14586a9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nltk/nltk"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3731.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/a510de7b-ffaf-4a83-9bf8-fa7e63f4bd2d"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NLTK: FileSystemPathPointer.open() sandbox check is dead code \u2014 arbitrary file read via file:// protocol",
  "upstream": [
    "PYSEC-2026-3731",
    "CVE-2026-65915",
    "GHSA-72r2-7mfr-5xr9"
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "nltk",
        "resource_purl": "pkg:pypi/nltk@3.10.3",
        "upstream_fixed_in": "3.10.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "safety",
        "purl": "pkg:brew/safety"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.3.1"
            },
            {
              "fixed": "3.8.1_1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/nltk@3.10.3",
        "name": "nltk",
        "resource": "nltk",
        "strategy": "registry",
        "subject_version": "3.10.3"
      }
    ]
  },
  "details": "### Summary\n\nThere\u0027s a logic bug in `FileSystemPathPointer.open()` inside `nltk/data.py`\nthat makes the sandbox check permanently inert. The guard condition is always\n`False` \u2014 meaning any file the process can read is accessible by passing a\n`file://` URL to `nltk.data.load()`.\n\n---\n\n### Details\n\nIn `nltk/data.py`, `FileSystemPathPointer.open()` was patched at some point\nwith a comment saying \"SECURITY PATCH ENFORCING SANDBOX\", but the check\ndoesn\u0027t work:\n```python\ndef open(self, encoding=None):\n    path = os.path.normpath(self._path)\n\n    # Block raw absolute reads such as \"/\" \"C:\\\\Windows\" etc.\n    if os.path.isabs(path) and path != os.path.normpath(self._path):\n        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n\n    stream = open(self._path, \"rb\")\n```\n\n`path` is set to `os.path.normpath(self._path)` on line 1, then compared\nagainst `os.path.normpath(self._path)` again in the condition. They are\nalways equal. The `ValueError` never fires.\n\nOn top of that, `__init__` already calls `os.path.abspath()` before storing\n`self._path`, so it\u0027s normalized before `open()` is even called. Running\n`normpath` on it again changes nothing.\n\nThe `stream = open(self._path, \"rb\")` line is always reached regardless of\nwhat path was passed in.\n\n---\n\n### PoC\n\nTested on Python 3.11, NLTK 3.9.1, Ubuntu 22.04.\n```python\nimport nltk\nfrom nltk.data import FileSystemPathPointer\n\n# direct construction\nptr = FileSystemPathPointer(\"/etc/passwd\")\nwith ptr.open() as f:\n    print(f.read(300))\n\n# via load() using file:// URL\ndata = nltk.data.load(\"file:///etc/passwd\", format=\"raw\")\nprint(data[:300])\n```\n\nBoth print file contents. No exception is raised.\n\n---\n\n### Impact\n\nAny app that lets users influence the string passed to `nltk.data.load()` or\n`nltk.data.find()` is exposed \u2014 web APIs, notebook servers, multi-tenant\npipelines. An attacker can read any file the process user has access to:\n`/etc/passwd`, `.env` files, private keys, `~/.aws/credentials`, etc.\n\n## Suggested Fix\n\n**File:** `nltk/data.py` \u2014 `FileSystemPathPointer.open()` (lines 378\u2013390)\n\n### What\u0027s wrong\n\nLine 387 compares `normpath(self._path)` against itself \u2014 always equal,\nso the `ValueError` never fires. The check is dead code.\n`__init__` already calls `abspath()` on construction, so re-running\n`normpath` inside `open()` changes nothing either.\n\n---\n\n### Fix\n\nValidate against the actual list of permitted data directories instead:\n```python\ndef open(self, encoding=None):\n    import nltk.data as _d\n    allowed = [os.path.abspath(p) for p in _d.path if p]\n    if allowed and not any(\n        os.path.commonpath([self._path, r]) == r for r in allowed\n    ):\n        raise ValueError(\n            f\"Access outside nltk_data blocked: {self._path!r}\"\n        )\n    stream = open(self._path, \"rb\")\n    if encoding is not None:\n        stream = SeekableUnicodeStreamReader(stream, encoding)\n    return stream\n```\n\n---\n\n### Why `commonpath` not `startswith`\n\n`startswith` is bypassable by a path that shares a prefix:\n```\n/tmp/nltk_data_evil\".startswith(\"/tmp/nltk_data\") \u2192 True  \u2717\ncommonpath([\"/tmp/nltk_data_evil\", \"/tmp/nltk_data\"]) \u2192 \"/tmp\"  \u2713\n```\n\n---\n\n### Diff\n```diff\n-    path = os.path.normpath(self._path)\n-    if os.path.isabs(path) and path != os.path.normpath(self._path):\n-        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n-\n+    import nltk.data as _d\n+    allowed = [os.path.abspath(p) for p in _d.path if p]\n+    if allowed and not any(\n+        os.path.commonpath([self._path, r]) == r for r in allowed\n+    ):\n+        raise ValueError(f\"Access outside nltk_data blocked: {self._path!r}\")\n     stream = open(self._path, \"rb\")\n```",
  "id": "BREW-safety-CVE-2026-65915",
  "modified": "2026-09-17T17:35:56Z",
  "published": "2026-09-02T09:53:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65915"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/pull/3522"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/commit/69db9911fdba914ceeaca7aec6e892d1b14586a9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nltk/nltk"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3731.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/a510de7b-ffaf-4a83-9bf8-fa7e63f4bd2d"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NLTK: FileSystemPathPointer.open() sandbox check is dead code \u2014 arbitrary file read via file:// protocol",
  "upstream": [
    "PYSEC-2026-3731",
    "CVE-2026-65915",
    "GHSA-72r2-7mfr-5xr9"
  ]
}

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:pypi/nltk",
          "product": "nltk",
          "vendor": "nltk",
          "versions": [
            {
              "lessThan": "3.10.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.10.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "653A48E1-BCC5-4342-B5DF-E8D71A83BCB9",
              "versionEndExcluding": "3.10.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files."
    }
  ],
  "id": "CVE-2026-65915",
  "lastModified": "2026-08-31T18:39:00.647",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-65915",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-24T19:20:34.826563Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-22T15:16:19.500",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "source": "disclosure@vulncheck.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.9.3"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "nltk"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65915"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-08T15:27:12Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThere\u0027s a logic bug in `FileSystemPathPointer.open()` inside `nltk/data.py`\nthat makes the sandbox check permanently inert. The guard condition is always\n`False` \u2014 meaning any file the process can read is accessible by passing a\n`file://` URL to `nltk.data.load()`.\n\n---\n\n### Details\n\nIn `nltk/data.py`, `FileSystemPathPointer.open()` was patched at some point\nwith a comment saying \"SECURITY PATCH ENFORCING SANDBOX\", but the check\ndoesn\u0027t work:\n```python\ndef open(self, encoding=None):\n    path = os.path.normpath(self._path)\n\n    # Block raw absolute reads such as \"/\" \"C:\\\\Windows\" etc.\n    if os.path.isabs(path) and path != os.path.normpath(self._path):\n        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n\n    stream = open(self._path, \"rb\")\n```\n\n`path` is set to `os.path.normpath(self._path)` on line 1, then compared\nagainst `os.path.normpath(self._path)` again in the condition. They are\nalways equal. The `ValueError` never fires.\n\nOn top of that, `__init__` already calls `os.path.abspath()` before storing\n`self._path`, so it\u0027s normalized before `open()` is even called. Running\n`normpath` on it again changes nothing.\n\nThe `stream = open(self._path, \"rb\")` line is always reached regardless of\nwhat path was passed in.\n\n---\n\n### PoC\n\nTested on Python 3.11, NLTK 3.9.1, Ubuntu 22.04.\n```python\nimport nltk\nfrom nltk.data import FileSystemPathPointer\n\n# direct construction\nptr = FileSystemPathPointer(\"/etc/passwd\")\nwith ptr.open() as f:\n    print(f.read(300))\n\n# via load() using file:// URL\ndata = nltk.data.load(\"file:///etc/passwd\", format=\"raw\")\nprint(data[:300])\n```\n\nBoth print file contents. No exception is raised.\n\n---\n\n### Impact\n\nAny app that lets users influence the string passed to `nltk.data.load()` or\n`nltk.data.find()` is exposed \u2014 web APIs, notebook servers, multi-tenant\npipelines. An attacker can read any file the process user has access to:\n`/etc/passwd`, `.env` files, private keys, `~/.aws/credentials`, etc.\n\n## Suggested Fix\n\n**File:** `nltk/data.py` \u2014 `FileSystemPathPointer.open()` (lines 378\u2013390)\n\n### What\u0027s wrong\n\nLine 387 compares `normpath(self._path)` against itself \u2014 always equal,\nso the `ValueError` never fires. The check is dead code.\n`__init__` already calls `abspath()` on construction, so re-running\n`normpath` inside `open()` changes nothing either.\n\n---\n\n### Fix\n\nValidate against the actual list of permitted data directories instead:\n```python\ndef open(self, encoding=None):\n    import nltk.data as _d\n    allowed = [os.path.abspath(p) for p in _d.path if p]\n    if allowed and not any(\n        os.path.commonpath([self._path, r]) == r for r in allowed\n    ):\n        raise ValueError(\n            f\"Access outside nltk_data blocked: {self._path!r}\"\n        )\n    stream = open(self._path, \"rb\")\n    if encoding is not None:\n        stream = SeekableUnicodeStreamReader(stream, encoding)\n    return stream\n```\n\n---\n\n### Why `commonpath` not `startswith`\n\n`startswith` is bypassable by a path that shares a prefix:\n```\n/tmp/nltk_data_evil\".startswith(\"/tmp/nltk_data\") \u2192 True  \u2717\ncommonpath([\"/tmp/nltk_data_evil\", \"/tmp/nltk_data\"]) \u2192 \"/tmp\"  \u2713\n```\n\n---\n\n### Diff\n```diff\n-    path = os.path.normpath(self._path)\n-    if os.path.isabs(path) and path != os.path.normpath(self._path):\n-        raise ValueError(f\"Direct absolute file access blocked: {path}\")\n-\n+    import nltk.data as _d\n+    allowed = [os.path.abspath(p) for p in _d.path if p]\n+    if allowed and not any(\n+        os.path.commonpath([self._path, r]) == r for r in allowed\n+    ):\n+        raise ValueError(f\"Access outside nltk_data blocked: {self._path!r}\")\n     stream = open(self._path, \"rb\")\n```",
  "id": "GHSA-72r2-7mfr-5xr9",
  "modified": "2026-09-08T15:27:12Z",
  "published": "2026-09-08T15:27:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65915"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/pull/3522"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/commit/69db9911fdba914ceeaca7aec6e892d1b14586a9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nltk/nltk"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3731.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/a510de7b-ffaf-4a83-9bf8-fa7e63f4bd2d"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "NLTK: FileSystemPathPointer.open() sandbox check is dead code \u2014 arbitrary file read via file:// protocol"
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "nltk"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "3.9.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-284"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-02T14:47:46Z",
    "nvd_published_at": "2026-08-22T15:16:19Z",
    "severity": "HIGH"
  },
  "details": "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of\u00a0GHSA-72r2-7mfr-5xr9. This link is maintained to preserve external references.\n\n## Original Description\nNLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files.",
  "id": "GHSA-79ph-w9m5-4v5m",
  "modified": "2026-09-02T14:47:46Z",
  "published": "2026-08-22T15:31:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65915"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Duplicate Advisory: FileSystemPathPointer.open() sandbox check is dead code \u2014 arbitrary file read via file:// protocol",
  "withdrawn": "2026-09-02T14:47:46Z"
}

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "nltk",
        "purl": "pkg:pypi/nltk"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.10.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8",
        "0.9",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6",
        "0.9.7",
        "0.9.8",
        "0.9.9",
        "2.0.1",
        "2.0.1rc1",
        "2.0.1rc2-git",
        "2.0.1rc3",
        "2.0.1rc4",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0b4",
        "2.0b5",
        "2.0b6",
        "2.0b7",
        "2.0b8",
        "2.0b9",
        "3.0.0",
        "3.0.0b1",
        "3.0.0b2",
        "3.0.1",
        "3.0.2",
        "3.0.3",
        "3.0.4",
        "3.0.5",
        "3.1",
        "3.2",
        "3.2.1",
        "3.2.2",
        "3.2.3",
        "3.2.4",
        "3.2.5",
        "3.3",
        "3.4",
        "3.4.1",
        "3.4.2",
        "3.4.3",
        "3.4.4",
        "3.4.5",
        "3.5",
        "3.5b1",
        "3.6",
        "3.6.1",
        "3.6.2",
        "3.6.3",
        "3.6.4",
        "3.6.5",
        "3.6.6",
        "3.6.7",
        "3.7",
        "3.8",
        "3.8.1",
        "3.9",
        "3.9.1",
        "3.9.2",
        "3.9.3",
        "3.9.4",
        "3.9b1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65915",
    "GHSA-72r2-7mfr-5xr9"
  ],
  "details": "NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files.",
  "id": "PYSEC-2026-3731",
  "modified": "2026-09-01T08:54:51.735365Z",
  "published": "2026-08-22T15:16:19.500Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    },
    {
      "type": "EVIDENCE",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-72r2-7mfr-5xr9"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "2.0~b9-0ubuntu4.1~esm6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@2.0~b9-0ubuntu4.1~esm6?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0~b9-0ubuntu4",
        "2.0~b9-0ubuntu4.1~esm2",
        "2.0~b9-0ubuntu4.1~esm4",
        "2.0~b9-0ubuntu4.1~esm5",
        "2.0~b9-0ubuntu4.1~esm6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "3.1-1ubuntu0.1+esm4"
          },
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.1-1ubuntu0.1+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.1-1ubuntu0.1+esm4?arch=source\u0026distro=esm-apps-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.4-1",
        "3.0.5-1",
        "3.1-1",
        "3.1-1ubuntu0.1",
        "3.1-1ubuntu0.1+esm1",
        "3.1-1ubuntu0.1+esm2",
        "3.1-1ubuntu0.1+esm3",
        "3.1-1ubuntu0.1+esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "3.2.5-1ubuntu0.1+esm4"
          },
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.2.5-1ubuntu0.1+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.2.5-1ubuntu0.1+esm4?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
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            }
          ],
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        }
      ],
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        "3.2.5-1",
        "3.2.5-1ubuntu0.1",
        "3.2.5-1ubuntu0.1+esm1",
        "3.2.5-1ubuntu0.1+esm2",
        "3.2.5-1ubuntu0.1+esm3",
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          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.4.5-2ubuntu0.1~esm4?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
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        "3.4.5-2",
        "3.4.5-2ubuntu0.1~esm1",
        "3.4.5-2ubuntu0.1~esm2",
        "3.4.5-2ubuntu0.1~esm3",
        "3.4.5-2ubuntu0.1~esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.7-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.7-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5-1",
        "3.6.5-1",
        "3.6.7-1",
        "3.7-1",
        "3.7-1ubuntu0.1~esm1",
        "3.7-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.8.1-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.8.1-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.1-1",
        "3.8.1-1ubuntu0.1~esm1",
        "3.8.1-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.9.2-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.9.2-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.9.1-2",
        "3.9.1-2build1",
        "3.9.2-1",
        "3.9.2-1ubuntu0.1~esm1",
        "3.9.2-1ubuntu0.1~esm2"
      ]
    }
  ],
  "aliases": [],
  "details": "NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files.",
  "id": "UBUNTU-CVE-2026-65915",
  "modified": "2026-09-02T16:22:32Z",
  "published": "2026-08-22T15:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-65915"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-65915"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nltk/nltk/security/advisories/ghsa-72r2-7mfr-5xr9"
    },
    {
      "type": "REPORT",
      "url": "https://security-tracker.debian.org/tracker/cve-2026-65915"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/cveproject/cvelistv5/tree/main/cves/2026/65xxx/cve-2026-65915.json"
    },
    {
      "type": "REPORT",
      "url": "https://nvd.nist.gov/vuln/detail/cve-2026-65915"
    },
    {
      "type": "REPORT",
      "url": "https://www.vulncheck.com/advisories/nltk-before-arbitrary-file-read-via-filesystempathpointer"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-65915"
  ]
}