{"apiVersion":"1.0","identifier":"CVE-2026-80206","description":"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.","publishedAt":"2026-08-26T11:16:40","lastModifiedAt":"2026-08-26T13:19:24","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-80206","cvssScore":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","epssProbability":0.0025,"riskScore":0.6,"affectedProduct":"NLTK","affectedVersions":"<3.10.3","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-80206","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-80206","en":"https://www.redsauce.net/en/cves/CVE-2026-80206","fr":"https://www.redsauce.net/fr/cves/CVE-2026-80206","pt":"https://www.redsauce.net/pt/cves/CVE-2026-80206","de":"https://www.redsauce.net/de/cves/CVE-2026-80206","sk":"https://www.redsauce.net/sk/cves/CVE-2026-80206","el":"https://www.redsauce.net/el/cves/CVE-2026-80206"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-80206"}}