{"schema_version":"1","data":[{"id":88,"advisory_id":"9cdc3b66-086d-4f89-9e21-014fb11a362a","revision":1,"source_id":"core-kev","source_url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-55040","source_published_at":"2026-08-18T00:00:00+00:00","published_at":"2026-10-24T20:40:17.573349+00:00","extraction_method":"structured","technologies":["core-kev","sharepoint"],"cve_ids":["CVE-2026-55040"],"event_types":["advisory"],"payload":{"kind":"advisory","title":"Microsoft SharePoint Weak Authentication Vulnerability","summary":"Microsoft SharePoint contains a weak authentication vulnerability which allows an unauthorized attacker to bypass a security feature over a network. CISA 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.","evidence":"kev:CVE-2026-55040","products":[{"name":{"value":"SharePoint","evidence":"/product"},"prerequisites":[],"fixed_versions":[],"affected_versions":[]}],"severity":"unknown","structured":{"id":"CVE-2026-55040","aliases":["CVE-2026-55040"],"affected":[],"modified":"2026-08-18T00:00:00.000Z","provider":"kev","references":["https://www.cisa.gov/known-exploited-vulnerabilities-catalog"],"exploitation":{"cwes":["CWE-1390"],"cveID":"CVE-2026-55040","notes":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040 ; 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-2026-55040","dueDate":"2026-08-21","product":"SharePoint","dateAdded":"2026-08-18","vendorProject":"Microsoft","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.","known_exploited":true,"shortDescription":"Microsoft SharePoint contains a weak authentication vulnerability which allows an unauthorized attacker to bypass a security feature over a network.","vulnerabilityName":"Microsoft SharePoint Weak Authentication Vulnerability","knownRansomwareCampaignUse":"Unknown"}},"related_cves":[{"value":"CVE-2026-55040","evidence":"/cveID"}],"security_relevant":true,"severity_evidence":null}}],"next_after":88,"next_before":88}