Natural Language Toolkit (NLTK): ReDoS in NLTK ReviewsCorpusReader FEATURES regex

SummaryReviewsCorpusReader extracts feature annotations of the form label followed by a bracketed signed digit e.g. a label then +2 from each review line, using the module-level FEATURES regex. The feature-label sub-pattern is unbounded — an optional greedy run of word-plus-whitespace groups...

Regular Expression Denial of Service (ReDoS)

Overview nltk is a Natural Language Toolkit NLTK is a Python package for natural language processing. Affected versions of this package are vulnerable to Regular Expression Denial of Service ReDoS via the FEATURES regex in nltk/corpus/reader/reviews.py. An attacker can hang...