{"id":"CVE-2026-42897","published":"2026-05-14T18:16:49Z","modified":"2026-10-26T14:10:00Z","title":"Microsoft Exchange Server Cross-Site Scripting Vulnerability","vendor":"Microsoft","product":"Microsoft","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"Microsoft Exchange Server contains a cross-site scripting flaw caused by improper neutralization of input during web page generation. An unauthenticated attacker over the network can perform spoofing against users, and exploitation requires that a user interact with a crafted element, such as by visiting a malicious page or link.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-30T13:36:37Z"},"cvss":{"score":6.1,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","provenance":"source","from":"NVD"},"epss":{"score":0.70662,"percentile":0.99393,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-05-15","dueDate":"2026-05-29","ransomware":false,"requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","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","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-05-14","exploitedFirstSeen":"2026-05-14","ransomware":false,"evidence":[{"url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-May","date":"2026-05-14"},{"url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","date":"2026-05-14"},{"url":"https://msrc.microsoft.com/update-guide/en-us/vulnerability/CVE-2026-42897","date":"2026-05-14"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-05-15"},{"url":"https://www.proofpoint.com/us/blog/threat-insight/more-cves-same-playbook-2026-vulnerability-exploitation-wild","date":"2026-05-27"},{"url":"https://asec.ahnlab.com/en/94360/","date":"2026-07-07"},{"url":"https://www.proofpoint.com/us/blog/threat-insight/cleaning-out-inboxes-ta488-comes-outlook-another-half-click-exploit","date":"2026-07-28"},{"url":"https://www.recordedfuture.com/blog/july-2026-cve-landscape","date":"2026-08-07"},{"url":"https://securelist.ru/tr/hacking-cat/117062/","date":"2026-09-11"},{"url":"https://ti.qianxin.com/uploads/2026/10/29/20ab59a356a884498644cff73d47a13a.pdf","date":"2026-10-29"}],"evidenceTotal":10,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 31, 2026","url":"https://otx.alienvault.com/pulse/6ae4aefab0c2191cecd41862","created":"2026-10-30"},{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"}],"provenance":"machine"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897","tags":["Mitigation","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42897","tags":["US Government Resource"]}],"techniques":[{"id":"T1189","name":"Drive-by Compromise","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: XSS delivered via user-visited web content","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"Improper neutralization of input during web page generation ('cross-site scripting')","start":0,"end":84}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1059.007","name":"JavaScript","tactics":["execution"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Spoofing via injected script in web page","mappingType":"primary_impact","evidence":[{"from":"description","quote":"allows an unauthorized attacker to perform spoofing over a network","start":114,"end":180}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-30343","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30343","exploited":true,"exploitedSince":"2026-05-15","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2026-05-15","earliestUrl":"https://github.com/atiilla/CVE-2026-42897","repos":[{"name":"atiilla/CVE-2026-42897","url":"https://github.com/atiilla/CVE-2026-42897","stars":5,"created":"2026-05-15"}]},"first":{"date":"2026-05-15","source":"PoC-in-GitHub","url":"https://github.com/atiilla/CVE-2026-42897"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1189"],"provenance":"ai"},{"stage":"primary","techniques":["T1059.007"],"provenance":"ai"}],"timeline":[{"date":"2026-05-14","kind":"published","label":"Published 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