CVE-2011-3187

mediumpriority · track · 29EPSS 0.067 · 94 %ileexploit · functionalEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · functional

Likely / severe?

6.67% (94th) EPSS

CVSS 4.3 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-28

The to_s method in actionpack/lib/action_dispatch/middleware/remote_ip.rb in Ruby on Rails 3.0.5 does not validate the X-Forwarded-For header in requests from IP addresses on a Class C network, which might allow remote attackers to inject arbitrary text into log files or bypass intended address parsing via a crafted header.

cvss

Technical severity, 0–10. One row per scoring source.

4.3

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.9–4.3

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v2.03.9lowAV:N/AC:M/Au:N/C:N/I:P/A:N/E:POCsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USprimaryCWE-20US

exploits (1)

Public proof-of-concept and weaponised exploit code.

EDB-35352Ruby on Rails 3.0.5 - 'WEBrick::HTTPRequest' Module HTTP Header Injectionfunctional · exploit_db

affected products (3)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
rubyonrails rails= 3.0.5nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
RubyGems actionpack2.3.0 → 2.3.13osvUSpkg:gem/actionpack

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-3vfw-7rcp-3xgmactionpack Improper Input Validation vulnerability2017-10-24ghsa · osvUS
The `to_s` method in `actionpack/lib/action_dispatch/middleware/remote_ip.rb` in Ruby on Rails 3.0.5 does not validate the X-Forwarded-For header in requests from IP addresses on a Class C network, which might allow remote attackers to inject arbitrary text into log files or bypass intended address parsing via a crafted header.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2011-08-29modified 2026-06-16

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+25194 more

references (27)

External citations — patches, advisories, analysis.

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