# CVE-2026-104182: stream-json: JSONC parser and verifier re-scan the whole accumulated comment on every input chunk

> An attacker can cause a denial of service by sending large JSONC comments in small chunks, triggering quadratic CPU usage in the stream-json library.

- **Severity:** Medium 6.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** CLEANSTART-2026-EJ44011, GHSA-hqr4-qq8f-hg3x

## What is CVE-2026-104182?

CVE-2026-104182 is a medium-severity denial of service vulnerability in uhop stream-json, published on 1 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### 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.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-104182?

2 open source packages ship an affected version, including stream-json.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `stream-json` | npm | All versions | 3.6.0 |
| `stream-json` | npm | All versions | 3.6.0 |

## How do I fix CVE-2026-104182?

Upgrade stream-json to 3.6.0 or later.

## Is CVE-2026-104182 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104182 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104182 and fix it if it is affected.

What it is: CVE-2026-104182 is a medium-severity denial of service vulnerability in uhop stream-json, published on 1 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104182 exists.

Affected packages and fixed versions:
- stream-json (npm): affected all versions; fixed in 3.6.0
- stream-json (npm): affected all versions; fixed in 3.6.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-104182/ (Markdown: https://insights.sbomify.com/CVE-2026-104182/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104182
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104182
- OSV: https://osv.dev/vulnerability/CVE-2026-104182

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104182/
Summaries are generated and may contain mistakes; the official description above is the record.