Vulnerability · Published Oct 1, 2026 · Assigned by GitHub_M
CVE-2026-104182stream-json: JSONC parser and verifier re-scan the whole accumulated comment on every input chunk
Medium 6.2
In plain English
A medium-severity security flaw in stream-json from uhop. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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, the JSONC parser at stream-json/jsonc/parser.js and verifier at stream-json/jsonc/verifier.js restart comment-terminator scanning from the opening slash whenever a block or line comment spans an input chunk, while retaining the accumulated comment buffer. Delivering a large valid comment across many small chunks therefore causes quadratic CPU work and can stall the Node.js event loop. The maintainer characterizes the attack vector as local because the documented JSONC input is locally owned or user-controlled configuration, rather than input intended for the open internet. This JSONC-only scope does not include the plain JSON parser, which advances through and discards consumed string and number data. This issue is fixed in version 3.6.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | stream-json | 3.6.0 | GHSA-hqr4-qq8f-hg3x |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| uhop | stream-json | < 3.6.0 |
Weakness: CWE-407 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/uhop/stream-json/security/advisories/GHSA-hqr4-qq8f-hg3x x_refsource_CONFIRM
- https://github.com/uhop/stream-json/commit/c0299dc168ce9455ef5ca5b6a0f6850ee7fa0468 x_refsource_MISC
- https://github.com/uhop/stream-json/releases/tag/3.6.0 x_refsource_MISC