{"cve":{"cve_id":"CVE-2021-32780","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.0123,"epss_percentile":0.65047,"epss_as_of":"2026-06-23","description":"Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.","published_at":"2021-08-24T20:55:10Z","last_modified_at":null,"cvss_v3_score":8.6,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-754"],"nvd_references":["https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history","https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:15:40.225685Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"C","value_label":"Changed"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"envoyproxy","vendor_name":"envoyproxy","product_slug":"envoy","product_name":"envoy","version_start":">= 1.19.0, < 1.19.1","version_start_inclusive":true,"version_end":">= 1.19.0, < 1.19.1","version_end_inclusive":true,"cpe23_uri":"cve5:envoyproxy:envoy:>= 1.19.0, < 1.19.1:>= 1.19.0, < 1.19.1"},{"vendor_slug":"envoyproxy","vendor_name":"envoyproxy","product_slug":"envoy","product_name":"envoy","version_start":">= 1.18.0, < 1.18.4","version_start_inclusive":true,"version_end":">= 1.18.0, < 1.18.4","version_end_inclusive":true,"cpe23_uri":"cve5:envoyproxy:envoy:>= 1.18.0, < 1.18.4:>= 1.18.0, < 1.18.4"}],"exploit_refs":[],"news":[],"references":[{"url":"https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history","source_type":"MISC","tags":[]},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2021-08-24T20:55:10Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:18:31.722192Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:18:31.722192Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:18:31.722192Z","label":"CVSS score revised","source":"cvelistv5"}]}