# CVE-2024-38355: Unhandled 'error' event in socket.io

> A specially crafted packet causes an uncaught exception, crashing the Node.js server process. Users should upgrade Socket.IO or add error listeners.

- **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jun 2024
- **Updated:** 3 Sep 2024
- **Also known as:** CLSA-2026-1789549941, GHSA-25hc-qcg6-38wj, ROOT-APP-NPM-CVE-2024-38355

## What is CVE-2024-38355?

CVE-2024-38355 is a high-severity denial of service vulnerability in socketio socket.io, published on 19 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. A specially crafted Socket.IO packet can trigger an uncaught exception on the Socket.IO server, thus killing the Node.js process. This issue is fixed by commit `15af22fc22` which has been included in `socket.io@4.6.2` (released in May 2023). The fix was backported in the 2.x branch as well with commit `d30630ba10`. Users are advised to upgrade. Users unable to upgrade may attach a listener for the "error" event to catch these errors.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2024-38355?

4 open source packages ship an affected version, including socket.io.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `socket.io` | npm | All versions | 2.5.1 |
| `socket.io` | npm | All versions | 2.5.1 |
| `socket.io` | npm | From 3.0.0 | 4.6.2 |
| `socket.io` | npm | From 3.0.0 | 4.6.2 |

## How do I fix CVE-2024-38355?

Upgrade socket.io to a fixed version for your release line: 2.5.1 or 4.6.2.

## Is CVE-2024-38355 being exploited?

There is no known exploitation of CVE-2024-38355 in the wild and no public exploit code.

Public exploit code:

- Proof of concept of CVE-2024-47554 (github_poc): https://github.com/PawelMurdzek/CVE-2024-38355-PoC

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-38355 and fix it if it is affected.

What it is: CVE-2024-38355 is a high-severity denial of service vulnerability in socketio socket.io, published on 19 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-38355 in the wild and no public exploit code.

Affected packages and fixed versions:
- socket.io (npm): affected all versions; fixed in 2.5.1
- socket.io (npm): affected all versions; fixed in 2.5.1
- socket.io (npm): affected from 3.0.0; fixed in 4.6.2
- socket.io (npm): affected from 3.0.0; fixed in 4.6.2

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-2024-38355/ (Markdown: https://insights.sbomify.com/CVE-2024-38355/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-38355
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-38355
- OSV: https://osv.dev/vulnerability/CVE-2024-38355

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-38355/
Summaries are generated and may contain mistakes; the official description above is the record.