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 ext…
Published: 2026-08-31 · CVSS: 8.3 · CVSS 4.0
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 is attacker-controlled — most importantly fork pull requests on public repositories — a $ref in that spec is fetched/read on the runner with no interaction required, enabling SSRF and disclosure of structured files on the runner. This issue has been patched in version 0.0.51.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7