CVE-2018-11627: Sinatra Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-mq35-wqvf-r23c
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2018-11627 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Sinatra libraries in the RubyGems ecosystem. The issue involves sinatra cross-site scripting vulnerability. Remediation is available by upgrading affected packages to version 2.0.2.

CVE-2018-11627 at a Glance

CVE Identifier CVE-2018-11627
GHSA Identifier GHSA-mq35-wqvf-r23c
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 Sinatra
Package Ecosystem RubyGems
Published Date
Last Updated

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-2018-11627

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

sinatra fixed: 2.0.2 
Upgrade sinatra to 2.0.2
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 sinatra

How to Check if You Are Affected

To determine whether your application is affected by CVE-2018-11627, inspect your project dependencies for Sinatra:

inspect dependencies for sinatra

Analyze the terminal output to locate any version of Sinatra in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.2), 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 Sinatra, 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

Sinatra before 2.0.2 has XSS via the 400 Bad Request page that occurs upon a params parser exception.

CVE-2018-11627 Affected Sinatra Versions

1 component(s)
Fixed Versions:
2.0.2
Product / Package Ecosystem Affected Versions Fixed Version
sinatra
gem/sinatra
RubyGems
≥ 2.0.0
< 2.0.2
2.0.2

References

NVD — CVE-2018-11627 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-11627
Sinatra Source Repository REPOSITORY
https://github.com/sinatra/sinatra/issues/1428
Security Fix Commit FIX COMMIT
https://github.com/sinatra/sinatra/commit/12786867d6faaceaec62c7c2cb5b0e2dc074d71a
access.redhat.com/errata/rhsa-2019:02... WEB
https://access.redhat.com/errata/RHSA-2019:0212
access.redhat.com/errata/rhsa-2019:03... WEB
https://access.redhat.com/errata/RHSA-2019:0315
Sinatra Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/sinatra/CVE-2018-11627.yml
Sinatra Source Repository REPOSITORY
https://github.com/sinatra/sinatra

Frequently Asked Questions

What is CVE-2018-11627?
CVE-2018-11627 is a security vulnerability in Sinatra involving Sinatra Cross-site Scripting vulnerability under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Sinatra versions are affected?
Affected versions include releases prior to 2.0.2 across affected packages: sinatra.
What version fixes CVE-2018-11627?
Upgrading to 2.0.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is sinatra affected?
Yes, sinatra is affected in releases prior to 2.0.2. Upgrade your dependency to 2.0.2 or later.
What is the CVSS score of CVE-2018-11627?
CVE-2018-11627 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-2018-11627?
CVE-2018-11627 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-2018-11627?
Run the dependency tree command: 'inspect dependencies for sinatra'. 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-mq35-wqvf-r23c",
  "modified" : "2023-01-23T21:24:55Z",
  "published" : "2018-06-05T21:32:06Z",
  "aliases" : [ "CVE-2018-11627" ],
  "summary" : "Sinatra Cross-site Scripting vulnerability",
  "details" : "Sinatra before 2.0.2 has XSS via the 400 Bad Request page that occurs upon a params parser exception.",
  "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" : "sinatra"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-11627"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sinatra/sinatra/issues/1428"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/sinatra/sinatra/commit/12786867d6faaceaec62c7c2cb5b0e2dc074d71a"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2019:0212"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2019:0315"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/sinatra/CVE-2018-11627.yml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/sinatra/sinatra"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:46:50Z",
    "nvd_published_at" : "2018-05-31T19:29:00Z"
  }
}