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.
CVE-2009-4492
- No confirmed exploitation signals yet
A fix is available — apply it.
- CVSS v3
- —
- EG Score
- 0.0(none)
- EPSS
- 96.5%
- KEV
- Not listed
Published
January 13, 2010
Last Modified
April 23, 2026
References (18)
- cve@mitrehttp://secunia.com/advisories/37949
- cve@mitrehttp://securitytracker.com/id?1023429
- cve@mitrehttp://www.redhat.com/support/errata/RHSA-2011-0908.html
- cve@mitrehttp://www.redhat.com/support/errata/RHSA-2011-0909.html
- cve@mitrehttp://www.ruby-lang.org/en/news/2010/01/10/webrick-escape-sequence-injection
- cve@mitrehttp://www.securityfocus.com/archive/1/508830/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/bid/37710
- cve@mitrehttp://www.ush.it/team/ush/hack_httpd_escape/adv.txt
- cve@mitrehttp://www.vupen.com/english/advisories/2010/0089
- af854a3a-2127-422b-91ae-364da2661108http://secunia.com/advisories/37949
- af854a3a-2127-422b-91ae-364da2661108http://securitytracker.com/id?1023429
- af854a3a-2127-422b-91ae-364da2661108http://www.redhat.com/support/errata/RHSA-2011-0908.html
- af854a3a-2127-422b-91ae-364da2661108http://www.redhat.com/support/errata/RHSA-2011-0909.html
- af854a3a-2127-422b-91ae-364da2661108http://www.ruby-lang.org/en/news/2010/01/10/webrick-escape-sequence-injection
- af854a3a-2127-422b-91ae-364da2661108http://www.securityfocus.com/archive/1/508830/100/0/threaded
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libruby1.9 (1.9.0.2-9ubuntu1.2) @ jaunty | 2026-05-29 | ubuntu |
| redhat | ruby-0:1.8.1-16.el4 | 2011-06-28 | redhat |
| redhat | ruby-0:1.8.5-19.el5_6.1 | 2011-06-28 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
RubyGems(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| webrick | 1.3.1, 1.4.0.beta1 | 1.4.0 | — |
All Vendor Advisories
(3)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 3× in last 7d / 31× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-05 02:26 UTCEPSS rescore
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- 2026-05-29 13:04 UTCVendor advisory
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Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- Exploit-DBEDB-33489✓ verifiedFirst seen Jan 11, 2010
Ruby 1.9.1 - WEBrick 'Terminal Escape Sequence in Logs' Command Injection
Open source ↗
Related CVEs(same vendor)
Frequently asked(4)
What is CVE-2009-4492?
When was CVE-2009-4492 disclosed?
Is CVE-2009-4492 actively exploited?
How do I remediate CVE-2009-4492?
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