CVE-2019-15587: Loofah Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-c3gv-9cxf-6f57
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CVSS 5.4
CWE-79
Published
Advisory Summary

CVE-2019-15587 is a MODERATE (CVSS 5.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Loofah libraries in the RubyGems ecosystem. The issue involves loofah allows cross-site scripting. Remediation is available by upgrading affected packages to version 2.3.1.

CVE-2019-15587 at a Glance

CVE Identifier CVE-2019-15587
GHSA Identifier GHSA-c3gv-9cxf-6f57
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Loofah
Package Ecosystem RubyGems
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
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-2019-15587

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

loofah fixed: 2.3.1 
Upgrade loofah to 2.3.1
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 loofah

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-15587, inspect your project dependencies for Loofah:

inspect dependencies for loofah

Analyze the terminal output to locate any version of Loofah in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.3.1), 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 Loofah, 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

In the Loofah gem for Ruby through v2.3.0, unsanitized JavaScript may occur in sanitized output when a crafted SVG element is republished.

CVE-2019-15587 Affected Loofah Versions

1 component(s)
Fixed Versions:
2.3.1
Product / Package Ecosystem Affected Versions Fixed Version
loofah
gem/loofah
RubyGems
< 2.3.1
2.3.1

References

NVD — CVE-2019-15587 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-15587
Loofah Source Repository REPOSITORY
https://github.com/flavorjones/loofah/issues/171
Security Fix Commit FIX COMMIT
https://github.com/flavorjones/loofah/commit/0c6617af440879ce97440f6eb6c58636456dc8ec
hackerone.com/reports/709009 WEB
https://hackerone.com/reports/709009
Loofah Source Repository REPOSITORY
https://github.com/flavorjones/loofah
Loofah Source Repository REPOSITORY
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2019-15587.yml
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4WK2UG7ORKRQOJ6E4XJ2NVIHYJES6BYZ
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XMCWPLYPNIWYAY443IZZJ4IHBBLIHBP5
Loofah Security Information SECURITY
https://security.netapp.com/advisory/ntap-20191122-0003
usn.ubuntu.com/4498-1 WEB
https://usn.ubuntu.com/4498-1
Loofah Security Information SECURITY
https://www.debian.org/security/2019/dsa-4554

Frequently Asked Questions

What is CVE-2019-15587?
CVE-2019-15587 is a security vulnerability in Loofah involving Loofah Allows Cross-site Scripting under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Loofah versions are affected?
Affected versions include releases prior to 2.3.1 across affected packages: loofah.
What version fixes CVE-2019-15587?
Upgrading to 2.3.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is loofah affected?
Yes, loofah is affected in releases prior to 2.3.1. Upgrade your dependency to 2.3.1 or later.
What is the CVSS score of CVE-2019-15587?
CVE-2019-15587 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2019-15587?
CVE-2019-15587 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-2019-15587?
Run the dependency tree command: 'inspect dependencies for loofah'. 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-c3gv-9cxf-6f57",
  "modified" : "2023-08-25T21:37:28Z",
  "published" : "2019-11-05T23:58:25Z",
  "aliases" : [ "CVE-2019-15587" ],
  "summary" : "Loofah Allows Cross-site Scripting",
  "details" : "In the Loofah gem for Ruby through v2.3.0, unsanitized JavaScript may occur in sanitized output when a crafted SVG element is republished.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "loofah"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.3.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-15587"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flavorjones/loofah/issues/171"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flavorjones/loofah/commit/0c6617af440879ce97440f6eb6c58636456dc8ec"
  }, {
    "type" : "WEB",
    "url" : "https://hackerone.com/reports/709009"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/flavorjones/loofah"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2019-15587.yml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4WK2UG7ORKRQOJ6E4XJ2NVIHYJES6BYZ"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XMCWPLYPNIWYAY443IZZJ4IHBBLIHBP5"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20191122-0003"
  }, {
    "type" : "WEB",
    "url" : "https://usn.ubuntu.com/4498-1"
  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2019/dsa-4554"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2019-10-24T20:44:29Z",
    "nvd_published_at" : "2019-10-22T21:15:00Z"
  }
}