NLTK before 3.10.3 fails to validate JVM options passed through the per-call options parameter in the java() function, allowing attackers to inject dangerous JVM flags. Attackers can supply malicious options like -agentpath, -javaagent, or @argfile to Stanford wrapper classes to achieve arbitrary code execution.

NLTK versions before 3.10.3 contain a vulnerability in the java() function that fails to validate JVM options passed via the per-call options parameter. This allows attackers to inject dangerous JVM flags such as -agentpath, -javaagent, or @argfile when interacting with Stanford wrapper classes. Successful exploitation can lead to arbitrary code execution on the affected system. The vulnerability is tracked as CVE-2026-79675 and has been assigned a high criticality rating. A fix is available in NLTK version 3.10.3 and later. Users of Stanford NLP wrapper classes within NLTK are particularly at risk. The issue was disclosed via GitHub Security Advisories and VulnCheck. Organizations using NLTK for natural language processing pipelines with Java-based Stanford tools should update immediately.