{"apiVersion":"1.0","identifier":"CVE-2026-78683","description":"NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the TransitionParser.parse() method (nltk/parse/transitionparser.py). The method calls pickle_load() with the default restricted=False, routing deserialization through WarningUnpickler, which does not override find_class() and therefore permits arbitrary class resolution. When an application loads an attacker-crafted model file, embedded pickle gadget chains execute arbitrary Python code with the privileges of the user running the application. NLTK provides a RestrictedUnpickler for safe deserialization, but it is not used by production code paths. Fixed in 3.10.0.","publishedAt":"2026-08-25T02:16:53","lastModifiedAt":"2026-08-25T16:17:27","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-78683","cvssScore":9.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","epssProbability":0.00276,"riskScore":0.98,"affectedProduct":"NLTK","affectedVersions":"<3.10.0","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-78683","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-78683","en":"https://www.redsauce.net/en/cves/CVE-2026-78683","fr":"https://www.redsauce.net/fr/cves/CVE-2026-78683","pt":"https://www.redsauce.net/pt/cves/CVE-2026-78683","de":"https://www.redsauce.net/de/cves/CVE-2026-78683","sk":"https://www.redsauce.net/sk/cves/CVE-2026-78683","el":"https://www.redsauce.net/el/cves/CVE-2026-78683"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-78683"}}