{"data":{"id":"ef4e1fe0-1a85-460e-acc5-85eecd823c9a","title":"CVE-2026-12261: A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model…","summary":"CVE-2026-12261 affects `nltk.downloader` in nltk/nltk versions <= 3.9.4. The downloader extracts package archives into shared namespaces such as `corpora/` and `taggers/` rather than package-isolated roots, and checks package integrity only after extraction. One package can therefore overwrite another package's trusted resources, and the changes take effect through ordinary NLTK APIs and persist across interpreter restarts, affecting downstream machine learning pipelines.","solution":"N/A -- no mitigation discussed in source.","labels":["security","research"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-12261","publishedAt":"2026-08-07T07:16:26.377Z","cveId":"CVE-2026-12261","cweIds":["CWE-284"],"cvssScore":null,"cvssSeverity":null,"severity":"high","attackType":["supply_chain","model_poisoning"],"issueType":"vulnerability","affectedPackages":["nltk@< 3.10.0 (fixed: 3.10.0)"],"affectedPackageNames":["nltk"],"affectedPackageRefs":["pypi:nltk"],"affectedVendors":[],"affectedVendorsRaw":["NLTK"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":"nltk.downloader cross-package resource and model poisoning via shared namespaces","headlinePromptVersion":"h1","cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":"unknown","epssScore":0.00211,"epssCheckedAt":"2026-11-09T12:10:44.315Z","kevDateAdded":null,"advisoryAliases":["GHSA-ffj6-66c4-86gw"],"affectedPackagesSource":"ghsa","affectedPackagesCheckedAt":"2026-10-10T03:45:44.492Z","patchAvailable":true,"disclosureDate":"2026-08-07T07:16:26.377Z","fixReleasedAt":"2026-07-08T02:39:09.753Z","daysToFix":-30,"fixCheckedAt":"2026-10-29T21:32:05.611Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["integrity","availability"],"aiComponentTargeted":"framework","llmSpecific":false,"classifierConfidence":0.8,"researchCategory":null,"atlasIds":["AML.T0010"],"fixes":[{"ecosystem":"pypi","name":"nltk","fixedVersion":"3.10.0","matchedVersion":"3.10.0","fixReleasedAt":"2026-07-08T02:39:09.753Z","daysToFix":-30,"match":"ecosystem","source":"tracked","status":"found","checkedAt":"2026-10-29T21:32:05.461Z"}]}}