HIGH 8.2 NVD
CVE-2026-80206
NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The _tgrep_node_action function compiles user-supp
NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The _tgrep_node_action function compiles user-supplied regular expressions embedded in /regex/ pattern nodes and executes them via re.search against tree node labels without any validation or timeout. An attacker who controls the tgrep pattern (e.g., via tgrep_positions() or tgrep_compile() exposed to external input) can supply a pattern that triggers catastrophic backtracking, causing indefinite CPU saturation that blocks the Python process.
References
- https://github.com/nltk/nltk/security/advisories/GHSA-w3v8-gmh9-3wv7
- https://www.vulncheck.com/advisories/nltk-3.10.2-regular-expression-denial-of-service-via-
- https://github.com/nltk/nltk/security/advisories/GHSA-w3v8-gmh9-3wv7
This high severity vulnerability with a CVSS score of 8.2 was published on 2026-08-26 via NVD.
vulnfeed aggregates 11364 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.