CVE-2018-16471: Rack Cross-Site Scripting Vulnerability

Q: What is CVE-2018-16471?

CVE-2018-16471 is a security vulnerability in Rack involving Rack vulnerable to Cross-site Scripting under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').

Q: Which Rack versions are affected?

Affected versions include releases prior to 2.0.6, 1.6.11 across affected packages: rack.

Q: What version fixes CVE-2018-16471?

Upgrading to 2.0.6, 1.6.11 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is rack affected?

Yes, rack is affected in releases prior to 2.0.6, 1.6.11. Upgrade your dependency to 2.0.6, 1.6.11 or later.

Q: What is the CVSS score of CVE-2018-16471?

CVE-2018-16471 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Q: What CWE is associated with CVE-2018-16471?

CVE-2018-16471 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).

Q: How can I check RubyGems dependencies for CVE-2018-16471?

Run the dependency tree command: 'inspect dependencies for rack'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-5r2p-j47h-mhpg

CVSS 6.1

CWE-79

Published 2018-11-15

Advisory Summary

CVE-2018-16471 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Rack libraries in the RubyGems ecosystem. The issue involves rack vulnerable to cross-site scripting. Remediation is available by upgrading affected packages to version 2.0.6, 1.6.11.

CVE-2018-16471 at a Glance

CVE Identifier CVE-2018-16471

GHSA Identifier GHSA-5r2p-j47h-mhpg

Severity MODERATE

CVSS v3.1 Base Score 6.1

CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Product Rack

Package Ecosystem RubyGems

Published Date 2018-11-15

Last Updated 2023-08-28

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)

Attack Complexity Low (AC:L)

Privileges Required None (PR:N)

User Interaction Required (UI:R)

Scope Changed (S:C)

Confidentiality Low (C:L)

Integrity Low (I:L)

Availability None (A:N)

How to Fix CVE-2018-16471

To remediate this vulnerability, upgrade all affected Rack dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

rack fixed: 2.0.6

Upgrade rack to 2.0.6

rack fixed: 1.6.11

Upgrade rack to 1.6.11

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for rack

How to Check if You Are Affected

To determine whether your application is affected by CVE-2018-16471, inspect your project dependencies for Rack:

inspect dependencies for rack

Analyze the terminal output to locate any version of Rack in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.6), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Rack, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the `scheme` method on `Rack::Request`. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.

CVE-2018-16471 Affected Rack Versions

2 component(s)

Fixed Versions:

2.0.61.6.11

Product / Package	Ecosystem	Affected Versions	Fixed Version
rack gem/rack	RubyGems	≥ 2.0.0 < 2.0.6	2.0.6
rack gem/rack	RubyGems	< 1.6.11	1.6.11

References

NVD — CVE-2018-16471 NVD

https://nvd.nist.gov/vuln/detail/CVE-2018-16471

Rack Source Repository REPOSITORY

https://github.com/rack/rack

Rack Source Repository REPOSITORY

https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2018-16471.yml

groups.google.com/forum/ WEB

https://groups.google.com/forum/#!topic/ruby-security-ann/NAalCee8n6o

groups.google.com/forum/ WEB

https://groups.google.com/forum/#!topic/rubyonrails-security/GKsAFT924Ag

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2018/11/msg00022.html

usn.ubuntu.com/4089-1 WEB

https://usn.ubuntu.com/4089-1

Rack Security Information SECURITY

http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00032.html

Rack Security Information SECURITY

http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html

Frequently Asked Questions

What is CVE-2018-16471?

CVE-2018-16471 is a security vulnerability in Rack involving Rack vulnerable to Cross-site Scripting under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').

Which Rack versions are affected?

Affected versions include releases prior to 2.0.6, 1.6.11 across affected packages: rack.

What version fixes CVE-2018-16471?

Upgrading to 2.0.6, 1.6.11 (or the latest patched release for your respective branch) resolves the vulnerability.

Is rack affected?

Yes, rack is affected in releases prior to 2.0.6, 1.6.11. Upgrade your dependency to 2.0.6, 1.6.11 or later.

What is the CVSS score of CVE-2018-16471?

CVE-2018-16471 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

What CWE is associated with CVE-2018-16471?

CVE-2018-16471 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).

How can I check RubyGems dependencies for CVE-2018-16471?

Run the dependency tree command: 'inspect dependencies for rack'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5r2p-j47h-mhpg",
  "modified" : "2023-08-28T12:48:11Z",
  "published" : "2018-11-15T15:59:08Z",
  "aliases" : [ "CVE-2018-16471" ],
  "summary" : "Rack vulnerable to Cross-site Scripting",
  "details" : "There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the `scheme` method on `Rack::Request`. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "rack"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.0.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "rack"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.6.11"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-16471"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rack/rack"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2018-16471.yml"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/forum/#!topic/ruby-security-ann/NAalCee8n6o"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/forum/#!topic/rubyonrails-security/GKsAFT924Ag"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2018/11/msg00022.html"
  }, {
    "type" : "WEB",
    "url" : "https://usn.ubuntu.com/4089-1"
  }, {
    "type" : "WEB",
    "url" : "http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00032.html"
  }, {
    "type" : "WEB",
    "url" : "http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:17:10Z",
    "nvd_published_at" : "2018-11-13T23:29:00Z"
  }
}

CVSS V3

6.1 MODERATE