CVE-2026-104183

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 v3 5.1 MEDIUM

5.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.5 / Impact : 2.5

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

01 Oct 2026, 21:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-01 21:17

Updated : 2026-10-02 18:47

NVD link : CVE-2026-104183

Mitre link : CVE-2026-104183

CVE.ORG link : CVE-2026-104183

JSON object : View

Products Affected

No product.

CWE

CWE-1321

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

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