CVE-2026-71513

Name of the Vulnerable Software and Affected Versions NLTK versions prior to 3.10.3

Description An issue exists in the AllowlistUnpickler component that fails to validate the global name, validating only the pickle module string. This allows attackers to resolve dotted names via attribute traversal to access callables outside the allowlisted namespace. An attacker can execute arbitrary commands by providing crafted untrusted transition-parser models that are loaded through the allowlisted pickle load function when TransitionParser.parse() is called.

Recommendations Update NLTK to version 3.10.3 or later.