Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-04T00:58:58 nltk: nltk: Arbitrary Code Execution via Untrusted JAR File Loading 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CWE-347

In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.

A flaw was found in the `nltk` library. Several Stanford interface classes within `nltk` are susceptible to arbitrary code execution. This vulnerability allows a local attacker to execute malicious code by providing an untrusted Java Archive (JAR) file, as the system lacks integrity verification for these files.

To mitigate this issue, users should ensure that only trusted Java Archive (JAR) files are processed by the `nltk` Stanford interface classes. Avoid loading JAR files from untrusted sources, as this vulnerability allows for arbitrary code execution. Implement strict input validation and source verification for any JAR files used with `nltk` to prevent the execution of malicious code. Exploit Intelligence Not affected exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Lightspeed Core Not affected lightspeed-core/lightspeed-stack-rhel9 OpenShift Lightspeed Not affected openshift-lightspeed/lightspeed-ocp-rag-rhel9 OpenShift Lightspeed Affected openshift-lightspeed/lightspeed-service-api-rhel9 OpenShift Lightspeed Not affected openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat Ansible Automation Platform 2 Under investigation ansible-automation-platform-25/lightspeed-chatbot-rhel8 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-llama-stack-core-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-ta-lmes-job-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-trustyai-nemo-guardrails-server-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 https://www.cve.org/CVERecord?id=CVE-2026-12252 https://nvd.nist.gov/vuln/detail/CVE-2026-12252 https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb