{"id":"CVE-2026-48819","state":"PUBLISHED","title":"Hey API: `buildClientParams` template: prototype chain substitution via unknown `$<slot>___proto__` key","description":"Hey API is an ecosystem for turning API specifications into production-ready code. Prior to 0.97.3, dist/clients/core/params.ts ships a runtime template copied into generated SDKs as params.gen.ts, and buildClientParams writes unknown slot-prefixed keys such as $body_, $headers_, $path_, and $query_ directly to the corresponding slot, allowing $query___proto__ alongside a legitimate q field to set params.query through params[\"query\"][\"__proto__\"] = value, call Object.setPrototypeOf(params.query, value), and expose inherited attacker-controlled keys during for..in iteration. This issue is fixed in version 0.97.3.","publishedAt":"2026-07-17T19:46:00.402Z","updatedAt":"2026-07-20T16:24:20.624Z","severity":{"score":4.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["hey-api openapi-ts"],"affected":[{"vendor":"hey-api","product":"openapi-ts","versions":[{"version":"< 0.97.3","status":"affected"}]}],"references":["https://github.com/hey-api/hey-api/security/advisories/GHSA-hhx9-57xq-r5rw","https://github.com/hey-api/hey-api/commit/023909137a15eff9c0263d3bcd116140076b214f","https://github.com/hey-api/hey-api/commit/da321a1529eb3c90d2109da870f514b915a60169","https://github.com/hey-api/hey-api/releases/tag/%40hey-api%2Fopenapi-ts%400.97.3"],"weaknesses":["CWE-1321"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48819.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48819","state":"PUBLISHED","datePublished":"2026-07-17T19:46:00.402Z","dateUpdated":"2026-07-20T16:24:20.624Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-22T20:57:10.976Z"},"containers":{"cna":{"title":"Hey API: `buildClientParams` template: prototype chain substitution via unknown `$<slot>___proto__` key","descriptions":[{"lang":"en","value":"Hey API is an ecosystem for turning API specifications into production-ready code. Prior to 0.97.3, dist/clients/core/params.ts ships a runtime template copied into generated SDKs as params.gen.ts, and buildClientParams writes unknown slot-prefixed keys such as $body_, $headers_, $path_, and $query_ directly to the corresponding slot, allowing $query___proto__ alongside a legitimate q field to set params.query through params[\"query\"][\"__proto__\"] = value, call Object.setPrototypeOf(params.query, value), and expose inherited attacker-controlled keys during for..in iteration. This issue is fixed in version 0.97.3."}],"affected":[{"vendor":"hey-api","product":"openapi-ts","versions":[{"version":"< 0.97.3","status":"affected"}]}],"references":[{"url":"https://github.com/hey-api/hey-api/security/advisories/GHSA-hhx9-57xq-r5rw","name":"https://github.com/hey-api/hey-api/security/advisories/GHSA-hhx9-57xq-r5rw","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/hey-api/hey-api/commit/023909137a15eff9c0263d3bcd116140076b214f","name":"https://github.com/hey-api/hey-api/commit/023909137a15eff9c0263d3bcd116140076b214f","tags":["x_refsource_MISC"]},{"url":"https://github.com/hey-api/hey-api/commit/da321a1529eb3c90d2109da870f514b915a60169","name":"https://github.com/hey-api/hey-api/commit/da321a1529eb3c90d2109da870f514b915a60169","tags":["x_refsource_MISC"]},{"url":"https://github.com/hey-api/hey-api/releases/tag/%40hey-api%2Fopenapi-ts%400.97.3","name":"https://github.com/hey-api/hey-api/releases/tag/%40hey-api%2Fopenapi-ts%400.97.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.8,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-17T19:46:00.402Z"},"source":{"advisory":"GHSA-hhx9-57xq-r5rw","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/hey-api/hey-api/security/advisories/GHSA-hhx9-57xq-r5rw","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-20T16:23:29.690460Z","id":"CVE-2026-48819","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-20T16:24:20.624Z"}}]}}}