{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-116577", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-10-26T15:03:39.035Z", "datePublished": "2026-10-26T20:20:22.104Z", "dateUpdated": "2026-10-26T20:20:22.104Z"}, "containers": {"cna": {"title": "Tornado: Quadratic CPU usage when parsing HTTP headers with line folding", "problemTypes": [{"descriptions": [{"cweId": "CWE-407", "lang": "en", "description": "CWE-407: Inefficient Algorithmic Complexity", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-770", "lang": "en", "description": "CWE-770: Allocation of Resources Without Limits or Throttling", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c"}, {"name": "https://github.com/tornadoweb/tornado/pull/3765", "tags": ["x_refsource_MISC"], "url": "https://github.com/tornadoweb/tornado/pull/3765"}, {"name": "https://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9", "tags": ["x_refsource_MISC"], "url": "https://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9"}, {"name": "https://github.com/tornadoweb/tornado/releases/tag/v6.6.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/tornadoweb/tornado/releases/tag/v6.6.0"}], "affected": [{"vendor": "tornadoweb", "product": "tornado", "versions": [{"version": "< 6.6", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-26T20:20:22.104Z"}, "descriptions": [{"lang": "en", "value": "Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, Tornado's HTTP header parser accepts obsolete line folding and repeatedly concatenates short continuation lines, causing quadratic CPU consumption on the IOLoop thread. An unauthenticated client can submit a header block containing many obsolete line-folding continuations before application code runs, blocking other connections served by the process. The cost grows with max_header_size, and only availability is affected. This issue is fixed in version 6.6."}], "source": {"advisory": "GHSA-pcg2-g6cj-q92c", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "tornado", "vendor": "tornadoweb", "versions": [{"status": "affected", "version": "< 6.6"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Tornado is a Python web framework and asynchronous networking library. Prior to 6.6, Tornado's HTTP header parser accepts obsolete line folding and repeatedly concatenates short continuation lines, causing quadratic CPU consumption on the IOLoop thread. An unauthenticated client can submit a header block containing many obsolete line-folding continuations before application code runs, blocking other connections served by the process. The cost grows with max_header_size, and only availability is affected. This issue is fixed in version 6.6."}], "id": "CVE-2026-116577", "lastModified": "2026-10-26T21:18:14.710", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-10-26T21:18:14.087", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9"}, {"source": "security-advisories@github.com", "url": "https://github.com/tornadoweb/tornado/pull/3765"}, {"source": "security-advisories@github.com", "url": "https://github.com/tornadoweb/tornado/releases/tag/v6.6.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-407"}, {"lang": "en", "value": "CWE-770"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "tornado: tornado: Denial of Service via obsolete HTTP header line folding", "id": "2561069", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2561069"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "status": "draft"}, "cwe": "CWE-1322", "details": ["A flaw was found in Tornado. An unauthenticated remote attacker can cause a Denial of Service (DoS) by sending crafted HTTP requests containing many folded header continuation lines. Processing these lines requires quadratic computational effort, consuming excessive CPU resources on the server's event loop and blocking legitimate incoming connections."], "name": "CVE-2026-116577", "package_state": [{"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Fix deferred", "package_name": "lightspeed-core/lightspeed-stack-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Fix deferred", "package_name": "lightspeed-core/rag-tool-cpu-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:lightspeed_core", "fix_state": "Fix deferred", "package_name": "lightspeed-core/rag-tool-cuda-12.9-rhel9", "product_name": "Lightspeed Core"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed:1", "fix_state": "Fix deferred", "package_name": "openshift-lightspeed/lightspeed-ocp-rag-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform-26/lightspeed-chatbot-rhel9", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Fix deferred", "package_name": "ansible-automation-platform-27/lightspeed-chatbot-rhel9", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "python-tornado", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "pcs", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "python-tornado", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-gaudi-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-rocm-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/disk-image-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-feature-server-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-llama-stack-core-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": 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(RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-th06-rocm64-torch291-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-th-torch-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-th-torch-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-th-torch-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-trustyai-nemo-guardrails-server-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": 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"rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "python-flit", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "python-pep517", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "python-tornado", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-cinder-backup", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-cinder-volume", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-haproxy", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-manila-share", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-mariadb", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-ovn-northd", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-rabbitmq", "product_name": "Red Hat OpenStack Platform 16.2"}, {"cpe": "cpe:/a:redhat:openstack:16.2", "fix_state": "Out of support scope", "package_name": "rhosp-rhel8/openstack-redis", "product_name": "Red Hat OpenStack Platform 16.2"}], "public_date": "2026-10-26T20:20:22Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-116577\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-116577\nhttps://github.com/tornadoweb/tornado/commit/1b7a1dc9f340f52de929852e8125aa12f25297c9\nhttps://github.com/tornadoweb/tornado/pull/3765\nhttps://github.com/tornadoweb/tornado/releases/tag/v6.6.0\nhttps://github.com/tornadoweb/tornado/security/advisories/GHSA-pcg2-g6cj-q92c"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,6.6)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "tornado", "source": "cna", "vendor": "tornadoweb"}, "product": "tornado", "vendor": "tornadoweb"}], "created": "2026-10-26T22:15:15.139666+00:00", "updated": "2026-10-27T14:15:03.615261+00:00", "vendors": ["tornadoweb", "tornadoweb$PRODUCT$tornado"]}