{"id":"CVE-2026-71513","title":"NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables …","summary":"NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables …","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cwe":["CWE-502"],"vendor":"nltk","product":"nltk","affected":["nltk < 3.10.3"],"patched":["nltk 3.10.3"],"published":"2026-08-22","updated":"2026-09-16","sourceUpdated":"2026-09-16T13:19:34.203","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-71513","references":[{"url":"https://github.com/nltk/nltk","label":"disclosure@vulncheck.com"},{"url":"https://github.com/nltk/nltk/blob/v3.10.2/nltk/picklesec.py#L119-L124","label":"disclosure@vulncheck.com"},{"url":"https://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nltk-through-remote-code-execution-via-allowlistunpickler-dotted-name-bypass","label":"disclosure@vulncheck.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71513"},{"url":"https://pypi.org/project/nltk"},{"url":"https://github.com/advisories/GHSA-5gh2-94qg-qppq"}],"tags":["nvd","osv","pip"],"epss":0.00793,"epssPercentile":0.54417,"aliases":["GHSA-5gh2-94qg-qppq","PYSEC-2026-3867"],"ecosystem":"pip","ingestedAt":"2026-08-23T04:42:14.972Z","slug":"CVE-2026-71513","body":"## Overview\n\nNLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.\n\n## Affected\n\n- `nltk < 3.10.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `nltk 3.10.3`\n\n## Package advisory (CVE-2026-71513)\n\nAffected packages:\n\n- `nltk >= 3.10.0, < 3.10.3`\n\nPatched in:\n\n- `nltk 3.10.3`\n\nSource: https://osv.dev/vulnerability/GHSA-5gh2-94qg-qppq","depth":"twilight","depthScore":49,"depthScoreParts":{"impact":48.4,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}