CVE-2026-80205: NLTK: ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions
NLTK’s Text.findall() and TokenSearcher.findall() methods accept user-supplied regular expressions and pass them to the Python re engine without timeout or validation, enabling catastrophic backtracking (ReDoS). This issue is isolated to the nltk.text module and was resolved in a prior commit.
References
- github.com/advisories/GHSA-rrv8-h7p8-rx55
- github.com/nltk/nltk/commit/d8e47539317b571ab1422981f5b9653d5eae1249
- github.com/nltk/nltk/pull/3674
- github.com/nltk/nltk/releases/tag/v3.10.0
- github.com/nltk/nltk/security/advisories/GHSA-rrv8-h7p8-rx55
- github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-3750.yaml
- nvd.nist.gov/vuln/detail/CVE-2026-80205
- www.vulncheck.com/advisories/nltk-before-3.10.0-redos-via-text-findall-unvalidated-regex
Code Behaviors & Features
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