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{"bugzilla": {"description": "nltk: NLTK: Remote Code Execution via AllowlistUnpickler dotted-name bypass", "id": "2521317", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521317"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.8", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-502", "details": ["NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.", "A flaw was found in NLTK. A remote attacker can achieve remote code execution by crafting untrusted transition-parser models. This vulnerability exists in the `AllowlistUnpickler`, which incorrectly validates only the pickle module string and not the global name. This allows attackers to bypass the allowlist by resolving dotted names through attribute traversal, leading to the execution of arbitrary commands when `TransitionParser.parse` loads a malicious model."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, avoid loading NLTK transition-parser models from untrusted or unverified sources. Ensure that applications processing such models implement robust input validation and only load models from known, secure origins."}, "name": "CVE-2026-71513", "package_state": [{"cpe": "cpe:/a:redhat:exploit_intelligence:0", "fix_state": "Not affected", "package_name": "exploit-intelligence-tech-preview/vulnerability-analysis-rhel9", "product_name": "Exploit Intelligence"}, {"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Affected", "package_name": "lightspeed-core/lightspeed-stack-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Affected", "package_name": "lightspeed-core/rag-tool-cpu-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Affected", "package_name": "lightspeed-core/rag-tool-cuda-12.9-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed", "fix_state": "Not affected", "package_name": "openshift-lightspeed/lightspeed-ocp-rag-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed", "fix_state": "Affected", "package_name": "openshift-lightspeed/lightspeed-service-api-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed", "fix_state": "Not affected", "package_name": "openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Not affected", "package_name": "ansible-automation-platform-25/lightspeed-chatbot-rhel8", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-llama-stack-core-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-ogx-core-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-ta-lmes-job-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-trustyai-garak-lls-provider-dsp-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-trustyai-nemo-guardrails-server-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Not affected", "package_name": "rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}], "public_date": "2026-08-22T13:34:07Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-71513\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-71513\nhttps://github.com/nltk/nltk\nhttps://github.com/nltk/nltk/blob/v3.10.2/nltk/picklesec.py#L119-L124\nhttps://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea\nhttps://www.vulncheck.com/advisories/nltk-through-remote-code-execution-via-allowlistunpickler-dotted-name-bypass"], "statement": "This is an Important vulnerability as it allows for remote code execution when processing untrusted NLTK transition-parser models. This can lead to arbitrary command execution and full system compromise in affected Red Hat products, including OpenShift Lightspeed and Lightspeed Core, which may process external data using NLTK.", "threat_severity": "Important"}

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