Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-09-15T15:18:31 tornado: Tornado: Denial of Service via memory amplification in multipart parsing 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CWE-770

Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.

A flaw was found in Tornado. This memory amplification vulnerability exists in the `parse_multipart_form_data` function, where multipart data is processed before validating the maximum number of parts. A remote attacker can exploit this by sending specially crafted multipart requests with numerous parts. This can lead to the creation of large temporary data structures, exhausting server memory and resulting in a Denial of Service (DoS) for the affected system.

This is an Important severity flaw. Applications using the Tornado web framework on Red Hat platforms are vulnerable to a denial of service due to a memory amplification issue in the `parse_multipart_form_data` function. A remote, unauthenticated attacker can send a crafted multipart request, causing the server to consume excessive memory and become unavailable. Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Exploit Intelligence Will not fix exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Lightspeed Core Affected lightspeed-core/lightspeed-stack-rhel9 Lightspeed Core Affected lightspeed-core/rag-tool-cpu-rhel9 Lightspeed Core Affected lightspeed-core/rag-tool-cuda-12.9-rhel9 Migration Toolkit for Applications 8 Affected mta/mta-solution-server-rhel9 OpenShift Lightspeed Will not fix openshift-lightspeed/lightspeed-ocp-rag-rhel9 Red Hat Ansible Automation Platform 2 Affected ansible-automation-platform-26/lightspeed-chatbot-rhel9 Red Hat Ansible Automation Platform 2 Affected ansible-automation-platform-27/lightspeed-chatbot-rhel9 Red Hat Enterprise Linux 10 Affected python-tornado Red Hat Enterprise Linux 10 Not affected rhel10/keylime-registrar Red Hat Enterprise Linux 10 Not affected rhel10/keylime-verifier Red Hat Enterprise Linux 8 Not affected pcs Red Hat Enterprise Linux 9 Affected python-tornado Red Hat Enterprise Linux 9 Not affected rhel9/keylime-registrar Red Hat Enterprise Linux 9 Not affected rhel9/keylime-verifier Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-cuda-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-gaudi-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-rocm-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/disk-image-cuda-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-feature-server-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-llama-stack-core-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-datascience-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-pytorch-llmcompressor-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-tensorflow-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-pipeline-runtime-tensorflow-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th06-cpu-torch210-py312-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-th06-cpu-torch291-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th06-cuda130-torch210-py312-rhel9 Red Hat OpenShift AI (RHOAI) Not affected rhoai/odh-th06-cuda130-torch291-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th06-rocm64-torch291-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th-torch-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th-torch-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-th-torch-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-trustyai-nemo-guardrails-server-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-tensorflow-cuda-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9 Red Hat OpenShift AI (RHOAI) Affected rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9 Red Hat OpenShift Container Platform 4 Affected openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 4 Affected python-flit Red Hat OpenShift Container Platform 4 Affected python-pep517 Red Hat OpenShift Container Platform 4 Affected python-tornado Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-cinder-backup Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-cinder-volume Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-haproxy Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-manila-share Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-mariadb Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-ovn-northd Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-rabbitmq Red Hat OpenStack Platform 16.2 Affected rhosp-rhel8/openstack-redis Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-cinder-backup Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-cinder-volume Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-haproxy Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-manila-share Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-mariadb Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-ovn-northd Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-rabbitmq Red Hat OpenStack Platform 17.1 Affected rhosp-rhel9/openstack-redis https://www.cve.org/CVERecord?id=CVE-2026-91990 https://nvd.nist.gov/vuln/detail/CVE-2026-91990 https://github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq https://www.vulncheck.com/advisories/tornado-before-6.5.8-memory-amplification-dos-via-multipart