{"cve":"CVE-2026-104183","nvd":{"published":"2026-10-01T21:17:19.197","modified":"2026-10-02T18:47:49.947","status":"Deferred","description":"stream-json is a micro-library of stream components for processing JSON and JSONC with a minimal memory footprint. Prior to 3.6.0, Assembler materializes object properties with plain assignment, so an input key named __proto__ invokes the inherited setter and causes parsed object prototype replacement instead of creating an own data property. Applications that make authorization or feature decisions from inherited values can therefore consume attacker-controlled properties, and a null prototype can disrupt code that expects Object.prototype methods. The researcher treats parsing untrusted JSON as part of the project contract, while the maintainer states that documented inputs are locally owned dumps, exports, or logs and characterizes the attack vector as local. The global Object.prototype is not polluted. This issue is fixed in version 3.6.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","score":5.1},"cwes":["CWE-1321"],"references":["https://github.com/uhop/stream-json/commit/2f2d35bbb547306991ded6487a279154d865a358","https://github.com/uhop/stream-json/releases/tag/3.6.0","https://github.com/uhop/stream-json/security/advisories/GHSA-mjw6-4jj6-33hc","https://github.com/uhop/stream-json/security/advisories/GHSA-mjw6-4jj6-33hc"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:57:46.668721662+00:00"},"epss":{"cve":"CVE-2026-104183","score":0.00195,"percentile":0.09143,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-mjw6-4jj6-33hc","url":"https://osv.dev/vulnerability/GHSA-mjw6-4jj6-33hc","summary":"stream-json has a prototype pollution issue: Assembler writes this.current[this.key] on plain objects","modified":"2026-10-05T23:00:04.253333698Z","packages":[{"ecosystem":"npm","name":"stream-json","purl":"pkg:npm/stream-json","ranges":["<3.6.0"],"fixed":["3.6.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}