{"id":"CVE-2026-58644","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-58644","generatedAt":"2026-10-28T09:26:44.674Z","title":"Microsoft SharePoint Deserialization of Untrusted Data Vulnerability","description":"Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.","published":"2026-07-14T17:17:14.000Z","lastModified":"2026-07-17T05:16:40.000Z","status":"Analyzed","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-502"],"affected":["microsoft/sharepoint server"],"epss":{"score":0.15873,"percentile":0.96869,"date":"2026-10-27","history":[{"date":"2026-09-21","score":0.60944,"percentile":0.99138},{"date":"2026-09-24","score":0.15873,"percentile":0.96764}]},"kev":{"listed":true,"dateAdded":"2026-07-16","dueDate":"2026-07-19","knownRansomwareCampaignUse":"Unknown","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-2026-58644 ; 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-2026-58644"},"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 19 July 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-09-24T00:00:00.000Z","detail":{"to":0.15873,"from":0.60944,"percentile":0.96764},"summary":"EPSS moved from 60.9% to 15.9% probability of exploitation in the next thirty days."},{"kind":"epss","label":"EPSS jump","at":"2026-09-21T00:00:00.000Z","detail":{"to":0.60944,"from":0.15873,"percentile":0.99138},"summary":"EPSS moved from 15.9% to 60.9% probability of exploitation in the next thirty days."}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644","tags":["Patch","Vendor Advisory"],"source":"secure@microsoft.com"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-58644","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-58644","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."}