{"id":"GHSA-v8w9-8mx6-g223","revision":"37884565e21b4e8c94e5f404b9054543","records":[{"revision":"37884565e21b4e8c94e5f404b9054543","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-v8w9-8mx6-g223","aliases":["CVE-2026-56763"],"title":"Hono vulnerable to Prototype Pollution possible through __proto__ key allowed in parseBody({ dot: true })","description":"## Summary\n\nWhen using `parseBody({ dot: true })` in HonoRequest, specially crafted form field names such as `__proto__.x` could create objects containing a `__proto__` property.\n\nIf the parsed result is later merged into regular JavaScript objects using unsafe merge patterns, this may lead to prototype pollution in the target object.\n\n## Details\n\nThe `parseBody({ dot: true })` feature supports dot notation to construct nested objects from form field names.\n\nIn previous versions, the `__proto__` path segment was not filtered. As a result, specially crafted keys such as `__proto__.x` could produce objects containing `__proto__` properties.\n\nWhile this behavior does not directly modify `Object.prototype` within Hono itself, it may become exploitable if the parsed result is later merged into regular JavaScript objects using unsafe merge patterns.\n\n## Impact\n\nApplications that merge parsed form data into regular objects using unsafe patterns (for example recursive deep merge utilities) may become vulnerable to prototype pollution.","state":0,"publishedAt":"2026-03-11T00:31:47+00:00","modifiedAt":"2026-10-02T22:45:04.5255877+00:00","affected":[{"ecosystem":"npm","name":"hono","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"4.12.7"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223","https://nvd.nist.gov/vuln/detail/CVE-2026-56763","https://github.com/honojs/hono/commit/ef902257e0beacbb83d2a9549b3b83e03514a6fe","https://github.com/honojs/hono","https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option"],"sourceUrl":"https://github.com/advisories/GHSA-v8w9-8mx6-g223","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-v8w9-8mx6-g223","identifiers":["GHSA-v8w9-8mx6-g223","CVE-2026-56763"]},"retained":false,"historicalAffected":[]}],"coverage":[]}