{"basis":"claimed","id":"CVE-2026-56164","name":"Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability","vendorProject":"Microsoft","product":"SharePoint Server","publishedAt":"2026-07-14","cvss":{"score":5.3,"severity":"MEDIUM","version":"3.1"},"exploited":{"kevAdded":"2026-07-14","dueDate":"2026-07-17","ransomware":false},"epss":{"score":0.01011,"percentile":0.63174,"date":"2026-11-02"},"coverage":{"cloudflare":{"status":"none","firstOn":null,"daysToRule":null},"aws":{"status":"none","firstOn":null,"daysToRule":null},"azure":{"status":"none","firstOn":null,"daysToRule":null},"google":{"status":"none","firstOn":null,"daysToRule":null},"fastly":{"status":"no_history","firstOn":null,"daysToRule":null},"f5":{"status":"none","firstOn":null,"daysToRule":null},"akamai":{"status":"no_source","firstOn":null,"daysToRule":null},"crs":{"status":"none","firstOn":null,"daysToRule":null}},"title":"Microsoft SharePoint Server Elevation of Privilege Vulnerability","description":"Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.","cwes":["CWE-306"],"vendors":[{"vendor":"cloudflare","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"aws","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"azure","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"google","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"fastly","status":"no_history","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"f5","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"akamai","status":"no_source","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]},{"vendor":"crs","status":"none","basis":"claimed","firstOn":null,"firstIsNew":false,"daysToRule":null,"daysAtMost":null,"freePlan":false,"claims":[]}],"updatedAt":"2026-11-04T04:17:38.196Z","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C","ssvc":{"exploitation":"active","automatable":"yes","technicalImpact":"partial"},"kevAction":"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.","kevNotes":"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","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164","name":"Microsoft SharePoint Server Elevation of Privilege Vulnerability","tags":["vendor-advisory","patch"]}],"affected":[{"vendor":"Microsoft","product":"Microsoft SharePoint Enterprise Server 2016","affected":["16.0.0 to before 16.0.5561.1001"],"fixed":[]},{"vendor":"Microsoft","product":"Microsoft SharePoint Server 2019","affected":["16.0.0 to before 16.0.10417.20175"],"fixed":[]},{"vendor":"Microsoft","product":"Microsoft SharePoint Server Subscription Edition","affected":["16.0.0 to before 16.0.19725.20434"],"fixed":[]}],"briefing":{"status":{"id":"known_exploited","label":"Known exploited"},"why":"CISA lists CVE-2026-56164 as exploited in the wild since 2026-07-14. It is reachable over the network without credentials or any user interaction (CVSS 5.3). No edge WAF vendor names it in a changelog, so default managed rules may or may not catch it.","who":"Teams running Microsoft Microsoft SharePoint Enterprise Server 2016 (16.0.0 to before 16.0.5561.1001), Microsoft Microsoft SharePoint Server 2019 (16.0.0 to before 16.0.10417.20175) and Microsoft Microsoft SharePoint Server Subscription Edition (16.0.0 to before 16.0.19725.20434). Prioritise internet-facing instances.","what_to_do":[{"text":"Find the version you run. In the SharePoint Management Shell:","command":{"where":"In the SharePoint Management Shell","command":"(Get-SPFarm).BuildVersion"}},{"text":"Apply the vendor's fix; the advisory lists the affected and fixed versions.","href":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164","linkText":"Microsoft SharePoint Server Elevation of Privilege Vulnerability"},{"text":"CISA's 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. US federal agencies must act by 2026-07-17."},{"text":"Review exposed instances for signs of compromise: it was exploited before many systems were patched, and a later patch does not undo access already gained."},{"text":"Do not rely on WAF defaults: no edge vendor names this CVE. Restrict access to the vulnerable component or add a custom rule until it is patched.","href":"#edge","linkText":"Edge coverage"},{"text":"Check which WAF sits in front of your site and whether it covers this CVE.","href":"#check","linkText":"Check your domain"}],"evidence":[{"heading":"CVE record","text":"CVSS 3.1 5.3 (medium). Weakness: CWE-306.","links":[{"label":"CVE-2026-56164","href":"https://www.cve.org/CVERecord?id=CVE-2026-56164"},{"label":"NVD","href":"https://nvd.nist.gov/vuln/detail/CVE-2026-56164"}]},{"heading":"Vendor advisory","text":"Fixes and mitigations the CVE record links to. Check affected builds against the vendor, including backports.","links":[{"label":"Microsoft SharePoint Server Elevation of Privilege Vulnerability","href":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164"}]},{"heading":"Exploit evidence","text":"No public exploit code found in Exploit-DB, Metasploit, nuclei-templates or GitHub. That does not mean none exists.","links":[]},{"heading":"CISA KEV","text":"Added 2026-07-14, federal due date 2026-07-17 (catalog 2026.11.03, checked 2026-11-04).","links":[{"label":"CISA KEV catalog","href":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-56164"}]},{"heading":"EPSS","text":"1.01% probability of exploitation activity in the next 30 days, higher than 63% of CVEs (2026-11-02).","links":[{"label":"FIRST EPSS","href":"https://api.first.org/data/v1/epss?cve=CVE-2026-56164"}]},{"heading":"WAF vendor statements","text":"No edge vendor changelog names it.","links":[]}],"agent_prompt":"Assess whether the infrastructure available to you is affected by CVE-2026-56164 (Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability). Perform a read-only assessment within your authorized access. Do not send exploit traffic, scan third-party systems, change configuration or restart services.\n\n1. Verify the CVE record at https://www.cve.org/CVERecord?id=CVE-2026-56164 and the vendor advisories (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164). Establish affected and fixed versions, including vendor backports. The record lists: Microsoft Microsoft SharePoint Enterprise Server 2016: affected 16.0.0 to before 16.0.5561.1001 | Microsoft Microsoft SharePoint Server 2019: affected 16.0.0 to before 16.0.10417.20175 | Microsoft Microsoft SharePoint Server Subscription Edition: affected 16.0.0 to before 16.0.19725.20434. Cite sources and retrieval dates; flag anything you cannot verify.\n2. Inventory deployments of Microsoft SharePoint Server: asset, environment, owner where known, installed version or build, and how you confirmed it (package metadata, a version endpoint, image tags), e.g. `(Get-SPFarm).BuildVersion` (in the SharePoint Management Shell). An image tag alone does not prove the running version.\n3. Identify which deployments are reachable from the internet or untrusted networks, and through which paths (direct origin, load balancer, CDN or WAF).\n4. Assess compensating controls separately from patch status. Current edge WAF coverage for this CVE: no edge WAF vendor names it. Live data: https://cve.vigilbase.com/api/v1/cves/CVE-2026-56164. Check whether the rule is enabled and in block mode on each path, and whether any path bypasses the WAF. A WAF rule is not a patch.\n5. It is known exploited (CISA KEV): review logs on exposed instances for signs of exploitation before and after patching.\n\nReturn a short summary and a table: asset | version/build | assessment (affected, fixed, not applicable, unknown) | exposure | compensating control | evidence | next action. List what you could not assess and the access needed to resolve it. Do not infer absence of compromise from patch status or a lack of alerts.\n\nRemediation guidance: Apply the vendor's fix; the advisory lists the affected and fixed versions. CISA's 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. US federal agencies must act by 2026-07-17.\nMore: https://cve.vigilbase.com/cve/CVE-2026-56164"},"measured":[],"sightings":null,"social":{"total":0,"first_seen":null,"daily":[{"day":"2026-10-22","posts":0},{"day":"2026-10-23","posts":0},{"day":"2026-10-24","posts":0},{"day":"2026-10-25","posts":0},{"day":"2026-10-26","posts":0},{"day":"2026-10-27","posts":0},{"day":"2026-10-28","posts":0},{"day":"2026-10-29","posts":0},{"day":"2026-10-30","posts":0},{"day":"2026-10-31","posts":0},{"day":"2026-11-01","posts":0},{"day":"2026-11-02","posts":0},{"day":"2026-11-03","posts":0},{"day":"2026-11-04","posts":0}],"top_posts":[],"exploit_repositories":[]}}