{"id":"CVE-2026-56164","published":"2026-07-14T17:17:09Z","modified":"2026-07-14T21:10:41Z","title":"Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability","vendor":"Microsoft","product":"SharePoint Server","tier":"core","eol":null,"description":{"text":"Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.","provenance":"source","from":"NVD"},"summary":{"text":"The vulnerability is a missing authentication check on a critical function in Microsoft Office SharePoint Server, a product from Microsoft. An unauthorized attacker with network access to the server can exploit it to elevate privileges, requiring no credentials and no user interaction.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-31T05:10:22Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.01011,"percentile":0.63142,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-07-14","dueDate":"2026-07-17","ransomware":false,"requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","notes":"https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56164 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-56164","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-07-14","exploitedFirstSeen":"2026-07-14","ransomware":false,"evidence":[{"url":"https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Jul","date":"2026-07-14"},{"url":"https://docs.google.com/spreadsheets/d/1lkNJ0uQwbeC1ZTRrxdtuPLCIl7mlUreoKfSIgajnSyY/edit","date":"2026-07-14"},{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164","date":"2026-07-14"},{"url":"https://previdian.com/CVE-2026-56164","date":"2026-07-14"},{"url":"https://www.cisa.gov/news-events/alerts/2026/07/14/cisa-urges-sharepoint-hardening-after-new-exploitations","date":"2026-07-14"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-07-14"},{"url":"https://www.tenable.com/blog/cve-2026-32201-cve-2026-45659-cve-2026-56164-faq-sharepoint-server-exploitation","date":"2026-07-16"},{"url":"https://www.resecurity.com/es/blog/article/from-web-request-to-domain-compromise-understanding-the-july-2026-sharepoint-attacks","date":"2026-07-18"},{"url":"https://research.checkpoint.com/2026/20th-july-threat-intelligence-report/","date":"2026-07-20"},{"url":"https://www.recordedfuture.com/blog/july-2026-cve-landscape","date":"2026-08-07"}],"evidenceTotal":12,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev 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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-306","name":"Missing Authentication for Critical Functionality"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56164","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: unauthenticated network attacker exploits exposed 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expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-44043","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-44043","exploited":true,"exploitedSince":"2026-07-14","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":2,"skipped":0,"earliest":"2026-07-15","earliestUrl":"https://github.com/sentinel-aidefense/CVE-2026-56164-EXP","repos":[{"name":"sentinel-aidefense/CVE-2026-56164-EXP","url":"https://github.com/sentinel-aidefense/CVE-2026-56164-EXP","stars":12,"created":"2026-07-15"},{"name":"sam00/POC-CVE-2026-56164-exploit","url":"https://github.com/sam00/POC-CVE-2026-56164-exploit","stars":2,"created":"2026-08-06"}]},"first":{"date":"2026-07-15","source":"PoC-in-GitHub","url":"https://github.com/sentinel-aidefense/CVE-2026-56164-EXP"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1068"],"provenance":"ai"}],"timeline":[{"date":"2026-07-14","kind":"published","label":"Published 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