{"id":"CVE-2026-45659","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-45659","generatedAt":"2026-10-28T13:14:36.862Z","title":"Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability","description":"Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.","published":"2026-05-22T23:16:56.000Z","lastModified":"2026-07-23T11:10:00.000Z","status":"Analyzed","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-502"],"affected":["microsoft/sharepoint server"],"epss":{"score":0.80242,"percentile":0.99616,"date":"2026-10-27","history":[{"date":"2026-09-24","score":0.02704,"percentile":0.85326},{"date":"2026-10-25","score":0.80242,"percentile":0.99615}]},"kev":{"listed":true,"dateAdded":"2026-07-01","dueDate":"2026-07-04","knownRansomwareCampaignUse":"Known","notes":"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.\nhttps://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"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 4 July 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.80242,"from":0.02704,"percentile":0.99615},"summary":"EPSS moved from 2.7% to 80.2% probability of exploitation in the next thirty days."},{"kind":"epss","label":"EPSS jump","at":"2026-09-24T00:00:00.000Z","detail":{"to":0.02704,"from":0.76075,"percentile":0.85326},"summary":"EPSS moved from 76.1% to 2.7% probability of exploitation in the next thirty days."}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659","tags":["Vendor Advisory"],"source":"secure@microsoft.com"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45659","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45659","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}