Azure Cosmos DB is a widely used cloud database; a network-accessible RCE could impact many organizations and core services.
CVE-2026-66803
Unauthorized remote code execution in Azure Cosmos DB via improper access control.
Is CVE-2026-66803 being exploited?
Not confirmed. CVE-2026-66803 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.55% probability of exploitation in the next 30 days.
How severe is CVE-2026-66803?
CVE-2026-66803 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-66803?
Yes. A fix has been recorded for CVE-2026-66803. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-66803 affect?
CVE-2026-66803 affects Microsoft Azure Cosmos DB, Azure Cosmos DB server-side functions, Managed Cosmos DB instances. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-66803?
Apply vendor fix when available; restrict network access, rotate keys, and monitor logs/alerts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution on Azure Cosmos DB instances, enabling attackers to run code, access/modify data, and pivot in cloud environments.
Immediate action required