Kiota: Unsafe oauth_card_path references in Kiota-generated API plugin manifests

Impact

When generating an API plugin manifest from an attacker-controlled or compromised OpenAPI description, Kiota copies x-ai-capabilities.response_semantics.oauth_card_path into the manifest without validating that it is a safe package-relative file reference. An attacker can supply parent-directory traversal, rooted paths, or absolute URIs instead of a card file within the plugin package.

The unsafe reference is propagated into the generated manifest. Its security effect depends on the downstream host's handling of the reference when the plugin is packaged and deployed. This is not local code execution or a file read performed by Kiota merely during generation. A consuming host that resolves the untrusted reference can cross the intended package boundary or use an unintended authentication card.

Affected versions

The affected NuGet packages are Microsoft.OpenApi.Kiota and Microsoft.OpenApi.Kiota.Builder, starting with version 1.25.1, which introduced this manifest field. The field remains unvalidated through version 1.34.1, including the separate 1.29.1 security-backport release. Version 1.35.0 fixes the issue.

Patches

Upgrade to Kiota 1.35.0 or later and regenerate affected plugin manifests. Kiota now applies the existing safe-file-reference validator to oauth_card_path, drops unsafe references, and emits a warning. Valid relative card paths remain supported.

• Fix: https://github.com/microsoft/kiota/pull/8055
• Fixed release: https://github.com/microsoft/kiota/releases/tag/v1.35.0

Workarounds

Generate plugins only from trusted, integrity-protected OpenAPI descriptions. Before packaging or deployment, review generated manifests and remove any oauth_card_path that is not a safe relative reference confined to the plugin package. Do not rely on validation of sibling manifest fields to validate this field.

Related advisories

GHSA-4jwf-m4wg-8p66 and GHSA-p5rm-jg5c-8c77 cover static_template.file. Their fixes do not enforce validation at the separate oauth_card_path emission site.