{"id":"CVE-2026-53507","state":"PUBLISHED","title":"oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs","description":"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.","publishedAt":"2026-08-31T18:57:41.097Z","updatedAt":"2026-09-01T14:46:09.533Z","severity":{"score":8.3,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["oasdiff oasdiff-action"],"affected":[{"vendor":"oasdiff","product":"oasdiff-action","versions":[{"version":"< 0.0.51","status":"affected"}]}],"references":["https://github.com/oasdiff/oasdiff-action/security/advisories/GHSA-fhj3-7267-7vv5","https://github.com/oasdiff/oasdiff-action/pull/128","https://github.com/oasdiff/oasdiff-action/pull/129","https://github.com/oasdiff/oasdiff-action/pull/130"],"weaknesses":["CWE-200","CWE-918","CWE-1188"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53507.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53507","state":"PUBLISHED","datePublished":"2026-08-31T18:57:41.097Z","dateUpdated":"2026-09-01T14:46:09.533Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T17:05:25.059Z"},"containers":{"cna":{"title":"oasdiff actions resolve external $refs by default, enabling SSRF and disclosure of structured files on pull-request runs","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"oasdiff","product":"oasdiff-action","versions":[{"version":"< 0.0.51","status":"affected"}]}],"references":[{"url":"https://github.com/oasdiff/oasdiff-action/security/advisories/GHSA-fhj3-7267-7vv5","name":"https://github.com/oasdiff/oasdiff-action/security/advisories/GHSA-fhj3-7267-7vv5","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/oasdiff/oasdiff-action/pull/128","name":"https://github.com/oasdiff/oasdiff-action/pull/128","tags":["x_refsource_MISC"]},{"url":"https://github.com/oasdiff/oasdiff-action/pull/129","name":"https://github.com/oasdiff/oasdiff-action/pull/129","tags":["x_refsource_MISC"]},{"url":"https://github.com/oasdiff/oasdiff-action/pull/130","name":"https://github.com/oasdiff/oasdiff-action/pull/130","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.3,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-200","lang":"en","description":"CWE-200: Exposure of Sensitive Information to an Unauthorized Actor","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1188","lang":"en","description":"CWE-1188: Insecure Default Initialization of Resource","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-31T18:57:41.097Z"},"source":{"advisory":"GHSA-fhj3-7267-7vv5","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-01T14:46:00.552397Z","id":"CVE-2026-53507","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-01T14:46:09.533Z"}}]}}}