{"cve":{"cve_id":"CVE-2021-0211","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":0.01317,"epss_percentile":0.67082,"epss_as_of":"2026-06-23","description":"An improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved Routing Protocol Daemon (RPD) service allows an attacker to send a valid BGP FlowSpec message thereby causing an unexpected change in the route advertisements within the BGP FlowSpec domain leading to disruptions in network traffic causing a Denial of Service (DoS) condition. Continued receipt of these update messages will cause a sustained Denial of Service condition. This issue affects Juniper Networks: Junos OS: All versions prior to 17.3R3-S10 with the exceptions of 15.1X49-D240 on SRX Series and 15.1R7-S8 on EX Series; 17.3 versions prior to 17.3R3-S10; 17.4 versions prior to 17.4R2-S12, 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R2-S8, 18.2R3-S6; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S6; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1; 19.4 versions prior to 19.4R1-S3, 19.4R2-S3, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S3 20.2R2; 20.3 versions prior to 20.3R1-S1, 20.3R2. Junos OS Evolved: All versions prior to 20.3R1-S1-EVO, 20.3R2-EVO.","published_at":"2021-01-15T17:35:57.520000Z","last_modified_at":null,"cvss_v3_score":10.0,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H","cvss_v3_severity":"CRITICAL","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":null,"nvd_references":["https://kb.juniper.net/JSA11101"],"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":"2026-06-28T23:14:43.525007Z"},"effective_severity":"CRITICAL","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":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os","product_name":"Junos OS","version_start":"15.1","version_start_inclusive":true,"version_end":"15.1R7-S8","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:15.1:15.1R7-S8"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper 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OS","version_start":"18.2","version_start_inclusive":true,"version_end":"18.2R2-S8, 18.2R3-S6","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:18.2:18.2R2-S8, 18.2R3-S6"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os","product_name":"Junos OS","version_start":"18.3","version_start_inclusive":true,"version_end":"18.3R3-S4","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:18.3:18.3R3-S4"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os","product_name":"Junos OS","version_start":"18.4","version_start_inclusive":true,"version_end":"18.4R1-S8, 18.4R2-S6, 18.4R3-S6","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:18.4:18.4R1-S8, 18.4R2-S6, 18.4R3-S6"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os","product_name":"Junos 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20.3R2","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:20.3:20.3R1-S1, 20.3R2"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os","product_name":"Junos OS","version_start":"15.1X49","version_start_inclusive":true,"version_end":"15.1X490-D240","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os:15.1X49:15.1X490-D240"},{"vendor_slug":"juniper-networks","vendor_name":"Juniper Networks","product_slug":"junos-os-evolved","product_name":"Junos OS Evolved","version_start":"unspecified","version_start_inclusive":true,"version_end":"20.3R1-S1-EVO, 20.3R2-EVO","version_end_inclusive":false,"cpe23_uri":"cve5:juniper-networks:junos-os-evolved:unspecified:20.3R1-S1-EVO, 20.3R2-EVO"}],"exploit_refs":[],"news":[],"references":[{"url":"https://kb.juniper.net/JSA11101","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2021-01-15T17:35:57.520000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:04:38.474392Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:04:38.474392Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:04:38.474392Z","label":"CVSS score revised","source":"cvelistv5"}]}