CVE-2026-40412 Overview
CVE-2026-40412 is an unrestricted file upload vulnerability in Microsoft Azure Orbital Spatio. The flaw allows an unauthenticated attacker to upload files of dangerous types and execute code over a network. Microsoft published the advisory through the Microsoft Security Response Center (MSRC). The weakness is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type).
The vulnerability requires no privileges, no user interaction, and is exploitable across the network. Successful exploitation grants the attacker code execution with the privileges of the service handling uploads.
Critical Impact
Unauthenticated remote code execution against Azure Orbital Spatio with full confidentiality, integrity, and availability impact.
Affected Products
- Microsoft Azure Orbital Spatio
Discovery Timeline
- 2026-05-22 - CVE-2026-40412 published to NVD
- 2026-05-27 - Last updated in NVD database
Technical Details for CVE-2026-40412
Vulnerability Analysis
The vulnerability resides in the file upload handling logic of Azure Orbital Spatio. The service accepts uploaded files without enforcing restrictions on file type, extension, or content. An attacker can submit a file containing executable server-side code, such as a web shell or script handler payload, and reach a path where the server processes the upload as code.
Because the attack vector is network-based and requires no authentication, exposure is broad. The scope is unchanged, meaning code executes within the security context of the vulnerable component. Confidentiality, integrity, and availability are all fully impacted, indicating arbitrary code execution rather than partial data exposure.
The EPSS probability is approximately 0.4% with a percentile near 61, indicating moderate likelihood of exploitation relative to other CVEs at publication time. No public proof-of-concept has been released, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
Root Cause
The root cause is missing or insufficient validation on uploaded file types. The service does not enforce an allowlist of permitted extensions and Multipurpose Internet Mail Extensions (MIME) types, does not verify file content against the declared type, and does not isolate uploaded content from executable execution paths. This combination permits attacker-supplied files to be interpreted and executed by the server.
Attack Vector
The attacker submits an HTTP request to the upload endpoint exposed by Azure Orbital Spatio. The request carries a file with a dangerous extension or polyglot content that the server later treats as executable. Once stored, the attacker triggers execution by requesting the uploaded resource or by relying on automatic server-side processing. Execution occurs without prior credentials or interaction from a legitimate user.
No verified exploit code is publicly available. Refer to the Microsoft Security Update Guide for vendor-supplied technical context.
Detection Methods for CVE-2026-40412
Indicators of Compromise
- Unexpected files with executable extensions (.aspx, .ashx, .jsp, .php, .exe, .dll) written to Azure Orbital Spatio storage paths.
- HTTP POST or PUT requests to upload endpoints originating from untrusted source IP addresses without prior authenticated session activity.
- Outbound network connections from the Azure Orbital Spatio service host to attacker-controlled infrastructure following an upload event.
- Spawned child processes from the upload-handling service that do not match the baseline process tree.
Detection Strategies
- Inspect web server and application logs for requests to upload handlers that return success responses for non-image, non-document content types.
- Correlate file write events in the upload directory with subsequent HTTP GET requests to the same path, which indicate web shell access.
- Monitor for process executions originating from web service accounts that invoke shells, cmd.exe, powershell.exe, or scripting interpreters.
- Apply CWE-434 detection patterns to file integrity monitoring rules covering Azure Orbital Spatio deployment paths.
Monitoring Recommendations
- Forward Azure activity logs, resource logs, and host telemetry to a centralized SIEM for correlation.
- Alert on any new executable artifact written to web-accessible directories of the Azure Orbital Spatio service.
- Track anomalous authentication and request patterns against the public endpoints of the service.
How to Mitigate CVE-2026-40412
Immediate Actions Required
- Apply the Microsoft-supplied fix referenced in the Microsoft Security Update Guide as soon as it is available in your tenant.
- Restrict network exposure of Azure Orbital Spatio upload endpoints to trusted networks using network security groups or private endpoints.
- Audit recent uploads for unexpected file types and quarantine any suspicious artifacts pending forensic review.
- Rotate credentials and access keys associated with the affected service if compromise is suspected.
Patch Information
Microsoft has issued guidance for CVE-2026-40412 through the Microsoft Security Update Guide. Because Azure Orbital Spatio is a cloud-hosted service, remediation is delivered by Microsoft on the service side. Customers should confirm their tenant has received the update and review the advisory for any required customer-side configuration changes.
Workarounds
- Disable or restrict access to file upload functionality until the patched service version is confirmed deployed.
- Place a web application firewall (WAF) in front of the service with rules blocking uploads of executable and script file extensions.
- Enforce strict content-type and extension allowlists at any upstream proxy or API gateway that fronts the service.
- Isolate the storage location for uploads from any path that permits server-side execution.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
