CVE-2026-53507 oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs

oasdiff-action is a GitHub Action that detects breaking changes in OpenAPI specs and post a review on every pull request. Before version 0.0.51, the oasdiff actions resolved external $refs in the OpenAPI spec by default allow-external-refs: true. When an action runs on a pull request whose spec i...