{"items":[{"id":"NVI-00010676","kind":"vulnerability","title":"NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection","revision":4,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected.","NVD lastModified does not establish freshness of every associated CPE record."],"lifecycle":"active","identifiers":["GHSA-5wp5-5229-5g6q","CVE-2026-12259"],"plain_summary":"GitHub lists this reviewed advisory for nltk. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-05977d8c07ea1713da3614aae1e1160c"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-27T07:58:08.000Z","value":"5.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2"},{"kind":"CVSS","as_of":"2026-10-23T22:10:00.160Z","value":"5.3 MEDIUM (3.0)","meaning":"security@huntr.dev severity; no combined Null risk score.","source_id":"sr-75ba6e19ca92fec137e0e1808086ba45"},{"kind":"CVSS","as_of":"2026-10-23T22:10:00.160Z","value":"6.5 MEDIUM (3.1)","meaning":"nvd@nist.gov severity; no combined Null risk score.","source_id":"sr-75ba6e19ca92fec137e0e1808086ba45"},{"kind":"EPSS","as_of":"2026-11-02T12:00:30.000Z","value":"0.101%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.00885. Missing scores are unknown.","source_id":"sr-05977d8c07ea1713da3614aae1e1160c"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2","url":"https://github.com/advisories/GHSA-5wp5-5229-5g6q","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-5wp5-5229-5g6q","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T22:06:46.371Z"},{"id":"sr-75ba6e19ca92fec137e0e1808086ba45","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-12259","basis":"official_catalog","notes":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","title":"CVE-2026-12259","publisher":"NIST National Vulnerability Database","observed_at":"2026-11-03T09:59:32.503Z"},{"id":"sr-05977d8c07ea1713da3614aae1e1160c","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-12259","publisher":"FIRST EPSS","observed_at":"2026-11-02T20:15:58.847Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-9983c5f5f8f89bf1e38d331e5b4be3a2"],"technology":"nltk","known_exclusions":[],"conditions_summary":"NLTK's package downloader in nltk/downloader.py does not verify file integrity after download and before extraction.\n\nThe download flow at lines 789-825:\n1. File is downloaded to a temp path via HTTP\n2. os.replace(tmp_filepath, filepath) moves it to the final location (line 799)\n3. Extraction begins via _unzip_iter() (line 825)\n\nBetween steps 2 and 3, there is no SHA-256 verification. The checksum logic exists in _pkg_status() (lines 982-1015) but it is only used BEFORE download as a status check (\"is this package already installed and up-to-date?\"). It is never called after download to verify the file that was actually received.\n\nAttack vectors:\n1. MITM during HTTP download (NLTK downloads from http:// by default on some mirrors)\n2. Race condition on shared filesystems (attacker replaces file between os.replace and _unzip_iter)\n3. DNS poisoning redirecting to attacker-controlled server\n\nPoC:\n```python\nimport nltk\nimport unittest.mock\nimport zipfile\nimport io\nimport os\n\n# Create a malicious zip that will be \"downloaded\"\nmalicious_zip = io.BytesIO()\nwith zipfile.ZipFile(malicious_zip, 'w') as zf:\n    zf.writestr('punkt_tab/tokenizers/punkt_tab/english.pickle', \n                b'MAL","public_affected_ranges":["<= 3.9.2"]}],"null_published_at":"2026-11-08T15:11:49.355Z","source_updated_at":"2026-10-27T07:58:08.000Z","source_disclosed_at":"2026-09-08T15:27:55.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Source facts changed; compare the preserved prior revision.","null_first_observed_at":"2026-10-31T22:06:46.371Z"},{"id":"NVI-00010676","kind":"vulnerability","title":"NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection","revision":3,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-5wp5-5229-5g6q","CVE-2026-12259"],"plain_summary":"GitHub lists this reviewed advisory for nltk. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-05977d8c07ea1713da3614aae1e1160c"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-27T07:58:08.000Z","value":"5.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2"},{"kind":"EPSS","as_of":"2026-11-02T12:00:30.000Z","value":"0.101%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.00885. Missing scores are unknown.","source_id":"sr-05977d8c07ea1713da3614aae1e1160c"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2","url":"https://github.com/advisories/GHSA-5wp5-5229-5g6q","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-5wp5-5229-5g6q","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T22:06:46.371Z"},{"id":"sr-05977d8c07ea1713da3614aae1e1160c","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-12259","publisher":"FIRST EPSS","observed_at":"2026-11-02T20:15:58.847Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-9983c5f5f8f89bf1e38d331e5b4be3a2"],"technology":"nltk","known_exclusions":[],"conditions_summary":"NLTK's package downloader in nltk/downloader.py does not verify file integrity after download and before extraction.\n\nThe download flow at lines 789-825:\n1. File is downloaded to a temp path via HTTP\n2. os.replace(tmp_filepath, filepath) moves it to the final location (line 799)\n3. Extraction begins via _unzip_iter() (line 825)\n\nBetween steps 2 and 3, there is no SHA-256 verification. The checksum logic exists in _pkg_status() (lines 982-1015) but it is only used BEFORE download as a status check (\"is this package already installed and up-to-date?\"). It is never called after download to verify the file that was actually received.\n\nAttack vectors:\n1. MITM during HTTP download (NLTK downloads from http:// by default on some mirrors)\n2. Race condition on shared filesystems (attacker replaces file between os.replace and _unzip_iter)\n3. DNS poisoning redirecting to attacker-controlled server\n\nPoC:\n```python\nimport nltk\nimport unittest.mock\nimport zipfile\nimport io\nimport os\n\n# Create a malicious zip that will be \"downloaded\"\nmalicious_zip = io.BytesIO()\nwith zipfile.ZipFile(malicious_zip, 'w') as zf:\n    zf.writestr('punkt_tab/tokenizers/punkt_tab/english.pickle', \n                b'MAL","public_affected_ranges":["<= 3.9.2"]}],"null_published_at":"2026-11-03T17:49:15.007Z","source_updated_at":"2026-10-27T07:58:08.000Z","source_disclosed_at":"2026-09-08T15:27:55.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-10-31T22:06:46.371Z"},{"id":"NVI-00010676","kind":"vulnerability","title":"NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-5wp5-5229-5g6q","CVE-2026-12259"],"plain_summary":"GitHub lists this reviewed advisory for nltk. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-6046252b357d8d4ba05f68de32a9dea7"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-27T07:58:08.000Z","value":"5.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2"},{"kind":"EPSS","as_of":"2026-10-31T12:00:27.000Z","value":"0.101%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.00887. Missing scores are unknown.","source_id":"sr-6046252b357d8d4ba05f68de32a9dea7"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2","url":"https://github.com/advisories/GHSA-5wp5-5229-5g6q","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-5wp5-5229-5g6q","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T22:06:46.371Z"},{"id":"sr-6046252b357d8d4ba05f68de32a9dea7","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-12259","publisher":"FIRST EPSS","observed_at":"2026-10-31T23:13:27.691Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-9983c5f5f8f89bf1e38d331e5b4be3a2"],"technology":"nltk","known_exclusions":[],"conditions_summary":"NLTK's package downloader in nltk/downloader.py does not verify file integrity after download and before extraction.\n\nThe download flow at lines 789-825:\n1. File is downloaded to a temp path via HTTP\n2. os.replace(tmp_filepath, filepath) moves it to the final location (line 799)\n3. Extraction begins via _unzip_iter() (line 825)\n\nBetween steps 2 and 3, there is no SHA-256 verification. The checksum logic exists in _pkg_status() (lines 982-1015) but it is only used BEFORE download as a status check (\"is this package already installed and up-to-date?\"). It is never called after download to verify the file that was actually received.\n\nAttack vectors:\n1. MITM during HTTP download (NLTK downloads from http:// by default on some mirrors)\n2. Race condition on shared filesystems (attacker replaces file between os.replace and _unzip_iter)\n3. DNS poisoning redirecting to attacker-controlled server\n\nPoC:\n```python\nimport nltk\nimport unittest.mock\nimport zipfile\nimport io\nimport os\n\n# Create a malicious zip that will be \"downloaded\"\nmalicious_zip = io.BytesIO()\nwith zipfile.ZipFile(malicious_zip, 'w') as zf:\n    zf.writestr('punkt_tab/tokenizers/punkt_tab/english.pickle', \n                b'MAL","public_affected_ranges":["<= 3.9.2"]}],"null_published_at":"2026-11-01T22:58:19.134Z","source_updated_at":"2026-10-27T07:58:08.000Z","source_disclosed_at":"2026-09-08T15:27:55.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-10-31T22:06:46.371Z"},{"id":"NVI-00010676","kind":"vulnerability","title":"NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-5wp5-5229-5g6q","CVE-2026-12259"],"plain_summary":"GitHub lists this reviewed advisory for nltk. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-9983c5f5f8f89bf1e38d331e5b4be3a2"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-27T07:58:08.000Z","value":"5.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-9983c5f5f8f89bf1e38d331e5b4be3a2","url":"https://github.com/advisories/GHSA-5wp5-5229-5g6q","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-5wp5-5229-5g6q","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T22:06:46.371Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-9983c5f5f8f89bf1e38d331e5b4be3a2"],"technology":"nltk","known_exclusions":[],"conditions_summary":"NLTK's package downloader in nltk/downloader.py does not verify file integrity after download and before extraction.\n\nThe download flow at lines 789-825:\n1. File is downloaded to a temp path via HTTP\n2. os.replace(tmp_filepath, filepath) moves it to the final location (line 799)\n3. Extraction begins via _unzip_iter() (line 825)\n\nBetween steps 2 and 3, there is no SHA-256 verification. The checksum logic exists in _pkg_status() (lines 982-1015) but it is only used BEFORE download as a status check (\"is this package already installed and up-to-date?\"). It is never called after download to verify the file that was actually received.\n\nAttack vectors:\n1. MITM during HTTP download (NLTK downloads from http:// by default on some mirrors)\n2. Race condition on shared filesystems (attacker replaces file between os.replace and _unzip_iter)\n3. DNS poisoning redirecting to attacker-controlled server\n\nPoC:\n```python\nimport nltk\nimport unittest.mock\nimport zipfile\nimport io\nimport os\n\n# Create a malicious zip that will be \"downloaded\"\nmalicious_zip = io.BytesIO()\nwith zipfile.ZipFile(malicious_zip, 'w') as zf:\n    zf.writestr('punkt_tab/tokenizers/punkt_tab/english.pickle', \n                b'MAL","public_affected_ranges":["<= 3.9.2"]}],"null_published_at":"2026-10-31T22:27:09.628Z","source_updated_at":"2026-10-27T07:58:08.000Z","source_disclosed_at":"2026-09-08T15:27:55.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-10-31T22:06:46.371Z"}],"next_cursor":null,"snapshot_revision":"42594"}