Easily map the attack path and prioritize which CVEs are a threat to your organization
Miggo AIGenerate vendor-ready rules for the observed attack patterns, plus reasoning and safe deployment guidance
Miggo AIRoot Cause AnalysisThe vulnerability is a Regular Expression Denial of Service (ReDoS) in the Pl196xCorpusReader of the NLTK library. The root cause is the use of inefficient regular expressions with lazy matching (.*?) in the read_block method of the TEICorpusView class. These regexes are used to parse TEI-formatted corpus files. An attacker can craft a malicious file with a large number of unmatched opening tags (e.g., <p>), which causes the regex engine to backtrack excessively, leading to a near-quadratic increase in CPU consumption and a denial of service. The vulnerability is exposed through several public methods of the Pl196xCorpusReader class, such as words(), tagged_words(), sents(), and paras(), which all rely on the vulnerable TEICorpusView.read_block method for parsing. The analysis is based on the detailed information provided in the security advisory GHSA-8mpw-7fpc-4gqj and the source code of a vulnerable version of pl196x.py. Although the exact commit that fixes the vulnerability could not be pinpointed from the provided information, the vulnerable functions and the nature of the vulnerability are clearly described in the advisory and visible in the source code.
TEICorpusView.read_blocknltk/corpus/reader/pl196x.py
Pl196xCorpusReader.wordsnltk/corpus/reader/pl196x.py
Pl196xCorpusReader.tagged_wordsnltk/corpus/reader/pl196x.py
Pl196xCorpusReader.sentsnltk/corpus/reader/pl196x.py
Pl196xCorpusReader.parasnltk/corpus/reader/pl196x.py
Pl196xCorpusReader.tagged_sentsnltk/corpus/reader/pl196x.py
Pl196xCorpusReader.tagged_parasnltk/corpus/reader/pl196x.py
| Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
|---|---|---|---|
| nltk | pip | <= 3.10.2 |