CVE-2009-4492· NVD / CVE Program· CNA mitre

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

Noroxi assessment

Priority: Monitor (action score 35/100)

Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 16.2% (FIRST EPSS); higher than 96.9% of all records.
No special conditions are required; it is repeatable.
Fixed version: irb (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4; ruby (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4; ruby-debuginfo (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4.

Low priority for now. Upgrade to irb (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4; ruby (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4; ruby-debuginfo (Red Hat:enterprise_linux:4::as) 0:1.8.1-16.el4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v2.0—Proof of concept Fix available

pre-auth RCE

Published: Jan 13, 2010
Updated: Jun 16, 2026
EPSS: 16.2% · 96th percentile
CWE: —

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 5 / 30 · 16.2%

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Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
ruby-lang	webrick	cpe:2.3:a:ruby-lang:webrick
ruby-lang	ruby	cpe:2.3:a:ruby-lang:ruby

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

ruby-lang webrick1.3.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Red Hat:enterprise_linux:4::as	irb	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-debuginfo	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-devel	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-docs	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-libs	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-mode	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:4::as	ruby-tcltk	before 0:1.8.1-16.el4	0:1.8.1-16.el4
Red Hat:enterprise_linux:5::server	ruby	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-debuginfo	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-devel	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-docs	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-irb	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-libs	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-mode	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-rdoc	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-ri	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
Red Hat:enterprise_linux:5::server	ruby-tcltk	before 0:1.8.5-19.el5_6.1	0:1.8.5-19.el5_6.1
RubyGems	webrick	before 1.4.0	1.4.0

Same product

ruby-lang: all records

Other highest-scoring records for the same primary product.

CVE-2008-1145Directory traversal vulnerability in WEBrick in Ruby 1.8 before 1.8.5-p115 and 1.8.6-p114, and 1.9 through 1.9.0-1, when running on systems
28Monitor
CVE-2025-6442Ruby WEBrick read_header HTTP Request Smuggling Vulnerability
23Monitor
CVE-2019-11879The WEBrick gem 1.4.2 for Ruby allows directory traversal if the attacker once had local access to create a symlink to a location outside of
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
red hat:irb	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-debuginfo	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-devel	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-docs	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-irb	0:1.8.5-19.el5_6.1 · Red Hat:enterprise_linux:5::server	Package registry (OSV)
red hat:ruby-libs	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-mode	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
red hat:ruby-rdoc	0:1.8.5-19.el5_6.1 · Red Hat:enterprise_linux:5::server	Package registry (OSV)
red hat:ruby-ri	0:1.8.5-19.el5_6.1 · Red Hat:enterprise_linux:5::server	Package registry (OSV)
red hat:ruby-tcltk	0:1.8.1-16.el4 · Red Hat:enterprise_linux:4::as	Package registry (OSV)
RubyGems:webrick	1.4.0	Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Exploit-DB entry	remote	2010-01-11

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

First PoCJan 11, 2010-3 d
PublishedJan 13, 2010
TodayOct 16, 2026+6120 d

EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

RubyHackerOne · paid

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

No special conditions are required; it is repeatable.

If successful

Confidentiality: P · data can be read
Integrity: P · data or configuration can be modified
Availability: P · the service can be disrupted

Attack complexity: Low
Confidentiality impact: P
Integrity impact: P
Availability impact: P

Weakness class (CWE)

—

CVSS vector

AV:N/AC:L/Au:N/C:P/I:P/A:P

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:47 PM UTC

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References

secunia.com/advisories/37949

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records