[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$foDXNcX_SQh5Fa2A1ezTMEmyg3xi0hV-6WViDrT4WaVM":3},{"article":4,"iocs":40},{"id":5,"title":6,"slug":7,"summary":8,"ai_summary":9,"brief":10,"full_text":11,"url":12,"image_url":13,"published_at":14,"ingested_at":15,"relevance_score":16,"entities":17,"category_id":27,"category":28,"article_tags":32},"bab30c21-801f-46ca-88dc-ebb502e82b0e","Microsoft Patches Exploited Exchange Server Vulnerability","microsoft-patches-exploited-exchange-server-vulnerability-2d6bc2","The company warned about zero-day attacks exploiting the Exchange Server vulnerability CVE-2026-42897 on May 14. The post Microsoft Patches Exploited Exchange Server Vulnerability appeared first on SecurityWeek.","Microsoft has released patches for an actively exploited zero-day vulnerability in Exchange Server, tracked as CVE-2026-42897. The flaw allows attackers to execute arbitrary JavaScript by sending specially crafted emails. CISA added the vulnerability to its KEV catalog, mandating federal agencies to address it by May 29.","Microsoft patches actively exploited Exchange Server vulnerability CVE-2026-42897.","Microsoft’s latest Patch Tuesday updates resolve an actively exploited Exchange Server vulnerability tracked as CVE-2026-42897. The tech giant warned Exchange users about zero-day attacks exploiting CVE-2026-42897 on May 14, when it provided temporary mitigations. CISA added the security hole to its Known Exploited Vulnerabilities (KEV) catalog on May 15, instructing federal agencies to address it by May 29. The vulnerability is a spoofing and XSS flaw that impacts Exchange Server Subscription Edition, 2016, and 2019. “An attacker could exploit this issue by sending a specially crafted email to a user. If the user opens the email in Outlook Web Access and certain interaction conditions are met, arbitrary JavaScript can be executed in the browser context,” Microsoft said in its advisory. The company released patches for the vulnerability on June 9 and urged customers to install the security updates as soon as possible. Advertisement. Scroll to continue reading. Microsoft learned about the vulnerability from a researcher who requested anonymity, and it’s still unclear who is behind the attacks or who the targets are. CISA’s KEV catalog includes two dozen Exchange vulnerabilities, and the data shows that while exploitation surged between 2021 and 2023, no new entries were added to the catalog in 2025, and only CVE-2026-42897 has been added so far in 2026. This indicates that Exchange exploitation is significantly less common today than during the peak years. Related: New Windows Zero-Day Exploit ‘RoguePlanet’ Released Related: ServiceNow Patches Vulnerability Exploited Against Some Customers Related: No Patch Planned for Exploited Arista EOS Vulnerability Written By Eduard Kovacs Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering. Daily Briefing Newsletter Subscribe to the SecurityWeek Email Briefing for the latest cybersecurity threats, trends, and expert insights. 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(Joshua Goldfarb) Flipboard Reddit Whatsapp Whatsapp Email","https:\u002F\u002Fwww.securityweek.com\u002Fmicrosoft-patches-exploited-exchange-server-vulnerability\u002F","https:\u002F\u002Fwww.securityweek.com\u002Fwp-content\u002Fuploads\u002F2026\u002F05\u002FExchange.jpg","2026-06-11T06:52:21+00:00","2026-06-11T08:00:18.322442+00:00",8,[18,21,24],{"name":19,"type":20},"Microsoft","vendor",{"name":22,"type":23},"Exchange Server","product",{"name":25,"type":26},"JavaScript","technology","80544778-fabb-4dcd-aa35-17492e5dcf4f",{"id":27,"icon":29,"name":30,"slug":31},null,"Vulnerabilities","vulnerabilities",[33,35],{"category":34},{"id":27,"icon":29,"name":30,"slug":31},{"category":36},{"id":37,"icon":29,"name":38,"slug":39},"e7b231c8-5f79-4465-8d38-1ef13aea5a14","Threat Intelligence","threat-intelligence",[41],{"type":42,"value":43,"context":44},"cve","CVE-2026-42897","Actively exploited Exchange Server vulnerability"]