{"id":"CVE-2026-70626","title":"NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root","summary":"NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does no…","severity":"medium","cvss":6.2,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-59"],"published":"2026-08-22","updated":"2026-08-22","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-70626","references":[{"url":"https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nltk-before-symlink-escape-via-corpusreader","label":"disclosure@vulncheck.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-70626"},{"url":"https://github.com/nltk/nltk/pull/3522"},{"url":"https://github.com/nltk/nltk/commit/1b0e519e2324bc1a273d56edee63e44d0ad85b48"},{"url":"https://github.com/nltk/nltk/releases/tag/3.9.4"},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3732.yaml"},{"url":"https://github.com/advisories/GHSA-r6gq-whwq-mvg9"},{"url":"https://github.com/nltk/nltk"}],"tags":["nvd","ghsa","pip","osv"],"ingestedAt":"2026-08-23T04:42:15.619Z","epss":0.00205,"epssPercentile":0.10752,"aliases":["GHSA-r6gq-whwq-mvg9","PYSEC-2026-3732"],"ecosystem":"pip","vendor":"nltk","product":"nltk","affected":["nltk <= 3.9.3"],"patched":["nltk 3.9.4"],"slug":"CVE-2026-70626","body":"## Overview\n\nNLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-70626)\n\nAffected packages:\n\n- `nltk <= 3.9.3`\n\nPatched in:\n\n- `nltk 3.9.4`\n\nSource: https://github.com/advisories/GHSA-r6gq-whwq-mvg9","depth":"sunlit","depthScore":34,"depthScoreParts":{"impact":34.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}