CVE-2020-26291: Urijs Hostname Spoofing Vulnerability

MODERATE
Advisory Identifier: GHSA-3329-pjwv-fjpg
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CVSS 6.5
CWE-20
Published
Advisory Summary

CVE-2020-26291 is a MODERATE (CVSS 6.5) hostname spoofing vulnerability (CWE-20: Improper Input Validation) affecting Urijs libraries in the npm ecosystem. The issue involves hostname spoofing via backslashes in url. Remediation is available by upgrading affected packages to version 1.19.4.

CVE-2020-26291 at a Glance

CVE Identifier CVE-2020-26291
GHSA Identifier GHSA-3329-pjwv-fjpg
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-20: Improper Input Validation
Affected Product Urijs
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2020-26291

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

urijs fixed: 1.19.4 
npm install urijs@1.19.4
Verify Direct and Transitive Dependencies

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

npm ls urijs

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2020-26291, inspect your project dependencies using npm:

npm ls urijs

Analyze the terminal output to locate any version of Urijs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.19.4), your application is affected.

Note: The npm ls urijs command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Urijs, 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

### Impact If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (`\`) character followed by an at (`@`) character. If the hostname is used in security decisions, the decision may be incorrect. Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior. Example URL: `https://expected-example.com\@observed-example.com` Escaped string: `https://expected-example.com\\@observed-example.com` (JavaScript strings must escape backslash) Affected versions incorrectly return `observed-example.com`. Patched versions correctly return `expected-example.com`. Patched versions match the behavior of other parsers which implement the [WHATWG URL specification](https://url.spec.whatwg.org/), including web browsers and [Node's built-in URL class](https://nodejs.org/api/url.html). ### Patches Version 1.19.4 is patched against all known payload variants. Version 1.19.3 has a partial patch but is still vulnerable to a payload variant. ### References https://github.com/medialize/URI.js/releases/tag/v1.19.4 (complete fix for this bypass) https://github.com/medialize/URI.js/releases/tag/v1.19.3 (partial fix for this bypass) [PR #233](https://github.com/medialize/URI.js/pull/233) (initial fix for backslash handling) ### For more information If you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js ### Reporter credit [Alesandro Ortiz](https://AlesandroOrtiz.com)

CVE-2020-26291 Affected Urijs Versions

1 component(s)
Fixed Versions:
1.19.4
Product / Package Ecosystem Affected Versions Fixed Version
urijs
npm/urijs
npm
< 1.19.4
1.19.4

References

GitHub Advisory / Wiki ADVISORY
https://github.com/medialize/URI.js/security/advisories/GHSA-3329-pjwv-fjpg
NVD — CVE-2020-26291 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26291
Security Fix Commit FIX COMMIT
https://github.com/medialize/URI.js/commit/b02bf037c99ac9316b77ff8bfd840e90becf1155
Urijs Source Repository REPOSITORY
https://github.com/medialize/URI.js
Urijs Release RELEASE
https://github.com/medialize/URI.js/releases/tag/v1.19.4
www.npmjs.com/advisories/1595 WEB
https://www.npmjs.com/advisories/1595
www.npmjs.com/package/urijs WEB
https://www.npmjs.com/package/urijs

Frequently Asked Questions

What is CVE-2020-26291?
CVE-2020-26291 is a security vulnerability in Urijs involving Hostname spoofing via backslashes in URL under CWE-20: Improper Input Validation.
Which Urijs versions are affected?
Affected versions include releases prior to 1.19.4 across affected packages: urijs.
What version fixes CVE-2020-26291?
Upgrading to 1.19.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is urijs affected?
Yes, urijs is affected in releases prior to 1.19.4. Upgrade your dependency to 1.19.4 or later.
What is the CVSS score of CVE-2020-26291?
CVE-2020-26291 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2020-26291?
CVE-2020-26291 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check npm dependencies for CVE-2020-26291?
Run the dependency tree command: 'npm ls urijs'. 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-3329-pjwv-fjpg",
  "modified" : "2022-11-30T03:23:13Z",
  "published" : "2020-12-30T23:40:48Z",
  "aliases" : [ "CVE-2020-26291" ],
  "summary" : "Hostname spoofing via backslashes in URL",
  "details" : "### Impact\nIf using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (`\\`) character followed by an at (`@`) character. If the hostname is used in security decisions, the decision may be incorrect.\n\nDepending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior.\n\nExample URL: `https://expected-example.com\\@observed-example.com`\nEscaped string: `https://expected-example.com\\\\@observed-example.com` (JavaScript strings must escape backslash)\n\nAffected versions incorrectly return `observed-example.com`. Patched versions correctly return `expected-example.com`. Patched versions match the behavior of other parsers which implement the [WHATWG URL specification](https://url.spec.whatwg.org/), including web browsers and [Node's built-in URL class](https://nodejs.org/api/url.html).\n\n### Patches\nVersion 1.19.4 is patched against all known payload variants. Version 1.19.3 has a partial patch but is still vulnerable to a payload variant.\n\n### References\nhttps://github.com/medialize/URI.js/releases/tag/v1.19.4 (complete fix for this bypass)\nhttps://github.com/medialize/URI.js/releases/tag/v1.19.3 (partial fix for this bypass)\n[PR #233](https://github.com/medialize/URI.js/pull/233) (initial fix for backslash handling)\n\n### For more information\nIf you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js\n\n### Reporter credit\n[Alesandro Ortiz](https://AlesandroOrtiz.com)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "urijs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.19.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/medialize/URI.js/security/advisories/GHSA-3329-pjwv-fjpg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-26291"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/medialize/URI.js/commit/b02bf037c99ac9316b77ff8bfd840e90becf1155"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/medialize/URI.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/medialize/URI.js/releases/tag/v1.19.4"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/advisories/1595"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/urijs"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-12-30T23:40:28Z",
    "nvd_published_at" : "2020-12-31T00:15:00Z"
  }
}