# CVE-2022-41940: Uncaught exception in engine.io

> A specially crafted HTTP request causes an uncaught exception in Engine.IO, crashing the Node.js process and denying service to users.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Nov 2022
- **Updated:** 22 Apr 2025
- **Also known as:** AZL-44820, GHSA-r7qp-cfhv-p84w, ROOT-APP-NPM-CVE-2022-41940

## What is CVE-2022-41940?

CVE-2022-41940 is a high-severity denial of service vulnerability in socketio engine.io, published on 22 Nov 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the engine.io package, including those who uses depending packages like socket.io. There is no known workaround except upgrading to a safe version. There are patches for this issue released in versions 3.6.1 and 6.2.1.

Weakness: CWE-248 (Uncaught Exception)

## Which versions are affected by CVE-2022-41940?

4 open source packages ship an affected version, including engine.io. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `engine.io` | npm | All versions | 3.6.1 |
| `engine.io` | npm | All versions | 3.6.1 |
| `engine.io` | npm | From 4.0.0 | 6.2.1 |
| `engine.io` | npm | From 4.0.0 | 6.2.1 |

Products: Socket Engine.io.

## How do I fix CVE-2022-41940?

Upgrade engine.io to a fixed version for your release line: 3.6.1 or 6.2.1.

## Is CVE-2022-41940 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2022-41940 exists.

## Other vulnerabilities in socketio engine.io

- [CVE-2026-59724](https://insights.sbomify.com/CVE-2026-59724/): Socket.IO: Engine.IO WebTransport SID DoS (high 7.5)
- [CVE-2026-59725](https://insights.sbomify.com/CVE-2026-59725/): Socket.IO: Engine.IO Polling Transport Connection Exhaustion (high 7.5)
- [CVE-2022-21676](https://insights.sbomify.com/CVE-2022-21676/): Uncaught Exception in engine.io (high 7.5)
- [CVE-2020-36048](https://insights.sbomify.com/CVE-2020-36048/): Resource exhaustion in engine.io (high 7.5)
- [CVE-2023-31125](https://insights.sbomify.com/CVE-2023-31125/): Uncaught exception in engine.io (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-41940 and fix it if it is affected.

What it is: CVE-2022-41940 is a high-severity denial of service vulnerability in socketio engine.io, published on 22 Nov 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2022-41940 exists.

Affected packages and fixed versions:
- engine.io (npm): affected all versions; fixed in 3.6.1
- engine.io (npm): affected all versions; fixed in 3.6.1
- engine.io (npm): affected from 4.0.0; fixed in 6.2.1
- engine.io (npm): affected from 4.0.0; fixed in 6.2.1

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-2022-41940/ (Markdown: https://insights.sbomify.com/CVE-2022-41940/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-41940
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-41940
- OSV: https://osv.dev/vulnerability/CVE-2022-41940

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-41940/
Summaries are generated and may contain mistakes; the official description above is the record.