{"id":"CVE-2026-53507","summary":"oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs","details":"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.","aliases":["GHSA-fhj3-7267-7vv5"],"modified":"2026-09-03T03:30:38.175364943Z","published":"2026-08-31T18:57:41.097Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-1188","CWE-200","CWE-918"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53507.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53507.json"},{"type":"ADVISORY","url":"https://github.com/oasdiff/oasdiff-action/security/advisories/GHSA-fhj3-7267-7vv5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53507"},{"type":"FIX","url":"https://github.com/oasdiff/oasdiff-action/pull/128"},{"type":"FIX","url":"https://github.com/oasdiff/oasdiff-action/pull/129"},{"type":"FIX","url":"https://github.com/oasdiff/oasdiff-action/pull/130"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/oasdiff/oasdiff-action","events":[{"introduced":"0"},{"fixed":"f30668f65075c93440bd59ce2de73ce9e78751f4"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.0.51"}],"source":["AFFECTED_FIELD","DESCRIPTION"]}}],"versions":["v0.0.50","v0.0.49","v0.0.48","v0.0.47","v0.0.46","v0.0.45","v0.0.44","v0.0.43","v0.0.42","v0.0.41","v0.0.40-beta.3","v0.0.40-beta.2","v0.0.40-beta.1","v0.0.39","v0.0.38","v0.0.37","v0.0.36","v0.0.35","v0.0.34","v0.0.33","v0.0.32","v0.0.31","v0.0.30","v0.0.21","v0.0.17","v0.0.16","v0.0.15","v0.0.14","v0.0.13","v0.0.12","v0.0.11","v0.0.10","v0.0.9","v0.0.8","v0.0.7","v0.0.6","v0.0.3","v0.0.2","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53507.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N"}]}