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CVE-2011-3187: 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…

MediumCVSS 4.3 · v2.0—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 19/100)

  • 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: 6.6% (FIRST EPSS); higher than 93.9% of all records.
  • Fixed version: actionpack (RubyGems) 2.3.13.

Low priority for now. Upgrade to actionpack (RubyGems) 2.3.13 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

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.

Published
Aug 29, 2011
Updated
Jun 16, 2026
EPSS
6.6% · 93th percentile

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Action score

19

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 6.6%

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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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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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.

VendorProduct
rubyonrailsrails

Affected versions

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

  • rubyonrails rails3.0.5

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12railsfrom 0—
RubyGemsactionpackfrom 2.3.0 · before 2.3.132.3.13

Same product

rubyonrails: all records

Other highest-scoring records for the same primary product.

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    90Now
  • CVE-2016-0752Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1…KEV
    89Now
  • CVE-2019-5420A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 can allow an attacker to guess the automatically…
    66This week

Published before and after this one in the same product

  • ← EarlierCVE-2011-2932Aug 29, 2011 · Cross-site scripting (XSS) vulnerability in activesupport/lib/active_support/core_ext/string/output_safety.rb in Ruby on Rails 2.x before 2.
    18Monitor
  • ← EarlierCVE-2011-3186Aug 29, 2011 · CRLF injection vulnerability in actionpack/lib/action_controller/response.rb in Ruby on Rails 2.3.x before 2.3.13 allows remote attackers…
    18Monitor
  • Later →CVE-2011-4319Nov 28, 2011 · Cross-site scripting (XSS) vulnerability in the i18n translations helper method in Ruby on Rails 3.0.x before 3.0.11 and 3.1.x before…
    17Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
RubyGems:actionpack2.3.13Package 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
SourceKindDate
Exploit-DB entryremote2011-02-16

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.

  1. First PoC-195 d
  2. Published
  3. TodayNov 15, 2026+5557 d

Bug bounty scope

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

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate.

Technical details

Attack conditions

    If successful

    Confidentiality
    none
    Integrity
    P · data or configuration can be modified
    Availability
    none
    Attack complexity
    M
    Confidentiality impact
    None
    Integrity impact
    P
    Availability impact
    None

    Weakness class (CWE)

    CWE-20 · Improper Input Validation

    CVSS vector

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

    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.

    References

    Show all references (5 more)

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

    All records