{"schema":"threatline.record/2","record":{"id":"CVE-2026-56763","aliases":["GHSA-v8w9-8mx6-g223"],"summary":"Hono vulnerable to Prototype Pollution possible through __proto__ key allowed in parseBody({ dot: true })","details":"## 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.","categories":["Libraries & packages"],"product":"hono","vendor":"Hono","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-v8w9-8mx6-g223","source_modified_at":"2026-10-02T22:36:06Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"hono"},"range":"< 4.12.7"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-56763","source_modified_at":"2026-07-14T14:30:12.573Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Hono","vendor":"Hono","versions":[{"lessThan":"4.12.7","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"4.12.7","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-v8w9-8mx6-g223","source_modified_at":"2026-10-02T22:45:04.525587715Z","fetched_at":"2026-10-23T18:55:00.935475Z","package":{"name":"hono","ecosystem":"npm","purl":"pkg:npm/hono"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.12.7"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-v8w9-8mx6-g223","source_modified_at":"2026-10-02T22:36:06Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"hono"},"version":"4.12.7"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-56763","source_modified_at":"2026-07-14T14:30:12.573Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Hono","ecosystem":null},"version":"4.12.7","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-v8w9-8mx6-g223","source_modified_at":"2026-10-02T22:45:04.525587715Z","fetched_at":"2026-10-23T18:55:00.935475Z","package":{"name":"hono","ecosystem":"npm","purl":"pkg:npm/hono"},"version":"4.12.7"}],"cvss":4.8,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00273,"percentile":0.18667,"score_date":"2026-10-23"},"published_at":"2026-07-11T13:00:59.084Z","modified_at":"2026-10-02T22:45:04.525587715Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-v8w9-8mx6-g223","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-02T22:36:06Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-56763","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-07-14T14:30:12.573Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-v8w9-8mx6-g223","fetched_at":"2026-10-23T18:55:00.935475Z","source_modified_at":"2026-10-02T22:45:04.525587715Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-56763","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/honojs/hono/security/advisories/GHSA-v8w9-8mx6-g223","tags":["vendor-advisory"]},{"url":"https://github.com/honojs/hono/commit/ef902257e0beacbb83d2a9549b3b83e03514a6fe","source":"GitHub Advisory Database"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56763","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://www.vulncheck.com/advisories/hono-prototype-pollution-via-proto-key-in-parsebody-with-dot-option","tags":["third-party-advisory"]},{"url":"https://github.com/advisories/GHSA-v8w9-8mx6-g223","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-07-14T14:29:52.929231Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-02T22:45:04.525587715Z","content_hash":"1d4a57371df588315a5ff169dee90513f161b068d55dede25accbe1f6202c6f7"}}