CVE-2026-70626

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 not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.

Affected Software

VendorProductVersion RangeStatus
nltknltk0 < 3.9.4affected
nltknltk3.9.4unaffected

Weaknesses

  • CWE-59: Improper Link Resolution Before File Access ('Link Following')

References