Disclosure summary
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.
Source-reported weakness categories
CWE-1321
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
GitHub Reviewed Security Advisories · GHSA-mjw6-4jj6-33hc
Open original source · Updated Oct 05, 2026
stream-json has a prototype pollution issue: Assembler writes this.current[this.key] on plain objects
Source severity: MEDIUM / 0
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| npm | stream-json | < 3.6.0 | 3.6.0 |
NIST National Vulnerability Database · NVD-CVE-2026-104183
Open original source · Updated Oct 02, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
Original records & references
PUBLISHED 2026-10-01T17:17:19-04:00
MODIFIED 2026-10-02T14:47:49-04:00
INGESTED 2026-10-06T11:45:14-04:00