Affects Microsoft Azure App Service — a widely used cloud platform. Authentication bypass enabling unauthenticated RCE can compromise tenants and cloud workloads organization-wide.
CVE-2026-77900
Auth bypass in Azure App Service allows unauthenticated remote code execution.
Is CVE-2026-77900 being exploited?
Not confirmed. CVE-2026-77900 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 0.49% probability of exploitation in the next 30 days.
How severe is CVE-2026-77900?
CVE-2026-77900 is rated Critical with a CVSS score of 9.8. 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-2026-77900?
Yes. A fix has been recorded for CVE-2026-77900. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-77900 affect?
CVE-2026-77900 affects Microsoft Azure App Service, Azure Web Apps, App Service Environments. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-77900?
Apply vendor patch when available; restrict App Service access, rotate credentials, and monitor logs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote code execution on Azure App Service; attackers can run arbitrary code, deploy payloads, access or exfiltrate tenant data and pivot within cloud environments.
Immediate action required