Code Generation Literal Injection in Kiota Python Generator Leads to Arbitrary Code Execution at Import Time.

The Kiota Python code generator is vulnerable to a code generation literal injection issue when processing malicious or untrusted OpenAPI specifications. Specifically, attacker-controlled enum value descriptions from x-ms-enum.values[].description can flow into generated Python files without newline sanitization, allowing injected content to escape a comment context and execute at module scope when the generated module is imported.

This issue requires user interaction in the form of generating a client from a malicious specification and importing the generated code, which is a common development and CI workflow.

Impact

A malicious OpenAPI specification can cause arbitrary Python code to be emitted into generated model files. The payload executes when the affected module is imported.

Potential impact includes

Credential theft from developer or CI environments Exfiltration of environment variables and secrets Source code disclosure Persistence via regenerated backdoored client output Who is impacted Developers generating Python SDKs from external or untrusted OpenAPI specs Teams with CI/CD automation that regenerates clients from remote specification URLs Any environment importing generated Python modules before manual review Vulnerability details Two gaps combine to enable exploitation:

Enum description cleanup gap

In KiotaBuilder.SetEnumOptions, enum option descriptions are assigned to Documentation.DescriptionTemplate without CleanupDescription on this path, allowing control characters such as newlines to propagate.

Python description sanitization gap

PythonConventionService.RemoveInvalidDescriptionCharacters escapes backslashes and triple quotes but did not remove carriage return/newline characters, unlike some other language convention services.

Exploit path

Malicious newline in x-ms-enum description is emitted through enum...