{"cve":{"cve_id":"CVE-2026-42897","is_kev":true,"kev_date_added":"2026-05-15","kev_vendor_project":"Microsoft","kev_product":"Microsoft","kev_vulnerability_name":"Microsoft Exchange Server Cross-Site Scripting Vulnerability","kev_short_description":"Microsoft Exchange Server contains a cross-site scripting vulnerability during web page generation in Outlook Web Access and when certain interaction conditions are met, arbitrary JavaScript can be executed in the browser context.","kev_required_action":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","kev_due_date":"2026-05-29","kev_known_ransomware":false,"kev_notes":"https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 ; https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service ; https://nvd.nist.gov/vuln/detail/CVE-2026-42897","kev_cwes":["CWE-79"],"epss_score":0.0564,"epss_percentile":0.91944,"epss_as_of":"2026-06-23","description":"Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.","published_at":"2026-05-14T17:00:36.515000Z","last_modified_at":null,"cvss_v3_score":8.1,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:F/RL:O/RC:C","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-79"],"nvd_references":["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897"],"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":"2026-06-24T00:09:31.350578Z","updated_at":"2026-06-28T23:30:22.092811Z"},"effective_severity":"HIGH","badges":["kev"],"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":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"N","value_label":"None"},{"metric":"E","name":"E","value":"F","value_label":"F"},{"metric":"RL","name":"RL","value":"O","value_label":"O"},{"metric":"RC","name":"RC","value":"C","value_label":"Changed"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"microsoft","vendor_name":"Microsoft","product_slug":"microsoft-exchange-server-2016-cumulative-update-23","product_name":"Microsoft Exchange Server 2016 Cumulative Update 23","version_start":"15.01.0.0","version_start_inclusive":true,"version_end":"15.01.2507.069","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-exchange-server-2016-cumulative-update-23:15.01.0.0:15.01.2507.069"},{"vendor_slug":"microsoft","vendor_name":"Microsoft","product_slug":"microsoft-exchange-server-2019-cumulative-update-14","product_name":"Microsoft Exchange Server 2019 Cumulative Update 14","version_start":"15.02.0.0","version_start_inclusive":true,"version_end":"15.02.1544.041","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-exchange-server-2019-cumulative-update-14:15.02.0.0:15.02.1544.041"},{"vendor_slug":"microsoft","vendor_name":"Microsoft","product_slug":"microsoft-exchange-server-2019-cumulative-update-15","product_name":"Microsoft Exchange Server 2019 Cumulative Update 15","version_start":"15.02.0.0","version_start_inclusive":true,"version_end":"15.02.1748.046","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-exchange-server-2019-cumulative-update-15:15.02.0.0:15.02.1748.046"},{"vendor_slug":"microsoft","vendor_name":"Microsoft","product_slug":"microsoft-exchange-server-subscription-edition-rtm","product_name":"Microsoft Exchange Server Subscription Edition RTM","version_start":"15.02.0.0","version_start_inclusive":true,"version_end":"15.02.2562.043","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-exchange-server-subscription-edition-rtm:15.02.0.0:15.02.2562.043"}],"exploit_refs":[],"news":[],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-05-14T17:00:36.515000Z","label":"CVE published","source":null},{"type":"cisa_reported","at":"2026-05-15T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"cvss_changed","at":"2026-06-28T17:54:12.493575Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:12.493575Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:12.493575Z","label":"CVSS score revised","source":"cvelistv5"}]}