{"id":"CVE-2025-71408","summary":"NLTK \u003c 3.9.3 Eval Injection via collocations.py Command-Line Arguments","details":"NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or sanitization, enabling an attacker to supply a Python expression that escapes the intended attribute lookup and executes arbitrary code including OS commands via the os module.","modified":"2026-07-29T03:30:37.003915421Z","published":"2026-07-24T21:07:49.610Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-95"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71408.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71408.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-71408"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/nltk-eval-injection-via-collocations-py-command-line-arguments"},{"type":"FIX","url":"https://github.com/nltk/nltk/commit/66f14096d952ec8f04934f515e027534bd4eb0ac"},{"type":"FIX","url":"https://github.com/nltk/nltk/pull/3465"},{"type":"FIX","url":"https://github.com/nltk/nltk/releases/tag/3.9.3"},{"type":"PACKAGE","url":"https://github.com/nltk/nltk"},{"type":"EVIDENCE","url":"https://aydinnyunus.github.io/2026/06/07/command-injection-nltk-collocations-eval/"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nltk/nltk","events":[{"introduced":"0"},{"fixed":"4154eb85e832f266660a09286c7e37e308292284"},{"fixed":"66f14096d952ec8f04934f515e027534bd4eb0ac"}],"database_specific":{"source":["DESCRIPTION","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"3.9.3"}]}}],"versions":["v3.9.2","3.9.2","3.9.1","3.9","3.8.2","3.8.1","3.8","3.7","3.6.7","3.6.6","3.6.5","3.6.2","3.6.1","3.6","3.5","3.5b1","3.4.4","3.4.3","3.4.1","3.4","3.3","3.2.5","3.2.4","3.2.3","3.2.2","3.2.1","3.2","3.1","3.0.5","3.0.4","3.0.3","3.0.2","3.0.0b1","3.0a4","2.0.1rc4","2.0.1rc3","2.0.1rc2","2.0.1rc1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-71408.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}