CVE-2026-65660: Microsoft SharePoint exploitation alert

CVE-2026-65660: what changed

CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 2026-09-25. Inclusion indicates evidence of exploitation; it does not establish that your own systems have been compromised.

Affected product

Microsoft SharePoint. Confirm affected versions against the vendor advisory.

CISA description

Microsoft SharePoint contains a code injection vulnerability which could allow an authorized attacker to execute code over a network.

Recommended response

Inventory affected deployments, check vendor guidance for fixes or mitigations, and verify the update was applied. Review available logs and incident-response guidance when exploitation is suspected.

Catalog context

CISA lists a remediation due date of 2026-09-28. Federal directive deadlines have a defined scope; other organizations should prioritize according to their exposure and risk. Ransomware campaign use is listed as unknown; “unknown” does not mean exploitation is absent.

Sources

• CISA Known Exploited Vulnerabilities catalog
• CVE-2026-65660 reference

Automated security brief based on CISA catalog data. Catalog addition date: 2026-09-25.