{"cve":{"cve_id":"CVE-2026-45659","is_kev":true,"kev_date_added":"2026-07-01","kev_vendor_project":"Microsoft","kev_product":"SharePoint Server","kev_vulnerability_name":"Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability","kev_short_description":"Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.","kev_required_action":"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.","kev_due_date":"2026-07-04","kev_known_ransomware":true,"kev_notes":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659 ; 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-2026-45659","kev_cwes":["CWE-502"],"epss_score":0.76075,"epss_percentile":0.99492,"epss_as_of":"2026-08-26","description":"Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.","published_at":"2026-05-22T22:04:33.517000Z","last_modified_at":"2026-07-23T11:10:00.120000Z","cvss_v3_score":8.8,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/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":"active","ssvc_automatable":false,"ssvc_technical_impact":"total","cwes":["CWE-502"],"nvd_references":["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659"],"vuln_status":"Analyzed","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":"2026-07-24T06:48:19.817091Z"},"effective_severity":"HIGH","badges":["kev","ransomware","news","epss"],"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":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"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":"H","value_label":"High"},{"metric":"E","name":"E","value":"U","value_label":"Unchanged"},{"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-sharepoint-enterprise-server-2016","product_name":"Microsoft SharePoint Enterprise Server 2016","version_start":"16.0.0","version_start_inclusive":true,"version_end":"16.0.5552.1002","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-sharepoint-enterprise-server-2016:16.0.0:16.0.5552.1002"},{"vendor_slug":"microsoft","vendor_name":"microsoft","product_slug":"microsoft-sharepoint-server-2019","product_name":"Microsoft SharePoint Server 2019","version_start":"16.0.0","version_start_inclusive":true,"version_end":"16.0.10417.20128","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-sharepoint-server-2019:16.0.0:16.0.10417.20128"},{"vendor_slug":"microsoft","vendor_name":"microsoft","product_slug":"microsoft-sharepoint-server-subscription-edition","product_name":"Microsoft SharePoint Server Subscription Edition","version_start":"16.0.0","version_start_inclusive":true,"version_end":"16.0.19725.20280","version_end_inclusive":false,"cpe23_uri":"cve5:microsoft:microsoft-sharepoint-server-subscription-edition:16.0.0:16.0.19725.20280"},{"vendor_slug":"microsoft","vendor_name":"microsoft","product_slug":"sharepoint-server","product_name":"sharepoint_server","version_start":null,"version_start_inclusive":null,"version_end":"16.0.19725.20280","version_end_inclusive":false,"cpe23_uri":"cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*"},{"vendor_slug":"microsoft","vendor_name":"microsoft","product_slug":"sharepoint-server","product_name":"sharepoint_server","version_start":"2016","version_start_inclusive":true,"version_end":"2016","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*"},{"vendor_slug":"microsoft","vendor_name":"microsoft","product_slug":"sharepoint-server","product_name":"sharepoint_server","version_start":"2019","version_start_inclusive":true,"version_end":"2019","version_end_inclusive":true,"cpe23_uri":"cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*"}],"exploit_refs":[],"news":[{"id":320,"source":"The Hacker News","url":"https://thehackernews.com/2026/07/sharepoint-rce-cve-2026-45659-added-to.html","title":"SharePoint RCE CVE-2026-45659 Added to CISA KEV After Active Exploitation","summary":"The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Wednesday added a high-severity flaw impacting Microsoft SharePoint Server to its Known Exploited Vulnerabilities (KEV) catalog, citing evidence of active exploitation.\n\nThe vulnerability, tracked as CVE-2026-45659 (CVSS score: 8.8), is a case of remote code execution arising from the deserialization of untrusted data. The issue","thumbnail_url":"https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMEHDpcGNoddFf8yfkJ1L21X61VSA66xZiVjYA5qdfJpZ8tyWxzRy7Il8fwcY59pRUm7mlNChrPHhjySmFLV-dHEIdZiOXj0ZDQ9Wv8yxgfU8qKm_ga3kYcNer9z85cj7KwtYkRuxGtPaNUL0ebiuM2SILSWMVr-fZtnVFejlJ24h48ECds-iMQBTW3vHb/s1600/cisa-ms.jpg","author":"info@thehackernews.com (The Hacker News)","published_at":"2026-07-02T05:46:45Z","fetched_at":"2026-07-02T06:35:35.523289Z","trending_score":4.146043179090403e-9,"cve_ids":["CVE-2026-45659"]}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-05-22T22:04:33.517000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:54:40.246008Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:40.246008Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:40.246008Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"cisa_reported","at":"2026-07-01T00:00:00Z","label":"Added to CISA KEV catalog","source":"kev"},{"type":"ssvc_changed","at":"2026-07-01T21:23:34.990835Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"first_article","at":"2026-07-02T05:46:45Z","label":"First news coverage","source":"The Hacker News"}]}