CVE-2021-3189: Slashify Open Redirect Vulnerability

MODERATE
Advisory Identifier: GHSA-f4hq-453j-p95f
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CVSS 6.1
CWE-601
Published
Advisory Summary

CVE-2021-3189 is a MODERATE (CVSS 6.1) open redirect vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Slashify libraries in the npm ecosystem. The issue involves open redirect in slashify. Remediation is available in the latest vendor maintenance releases.

CVE-2021-3189 at a Glance

CVE Identifier CVE-2021-3189
GHSA Identifier GHSA-f4hq-453j-p95f
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Slashify
Package Ecosystem npm
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:3.1/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-2021-3189

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

slashify fixed: Latest secure release 
npm install slashify@Latest secure release
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 slashify

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-3189, inspect your project dependencies using npm:

npm ls slashify

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

Note: The npm ls slashify 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-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Slashify, 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

The package is an Express middleware that normalises routes by stripping any final slash, redirecting, for example, `bookings/latest/` to `bookings/latest`. However, it does not validate the path it redirects to in any way. In particular, if the path starts with two slashes (or two backslashes, or a slash and a backslash, etc.) it may redirect to a different domain. Consider the [example from the docs](https://www.npmjs.com/package/slashify#usage). Assume we have run it and started a server on `localhost:3000`, then visiting `localhost:3000///github.com/` redirects you to https://github.com. ## Recommendation This vulnerability is currently un-patched in the `slashify` package so there is no known safe version of this package. Discontinuing use of `slashify` is recommended.

CVE-2021-3189 Affected Slashify Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
slashify
npm/slashify
npm
≤ 1.0.0

References

NVD — CVE-2021-3189 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3189
Slashify Source Repository REPOSITORY
https://github.com/divshot/slashify
Slashify Security Information SECURITY
https://security.netapp.com/advisory/ntap-20210401-0004
GitHub Advisory / Wiki ADVISORY
https://securitylab.github.com/advisories/GHSL-2020-199-open-redirect-slashify
www.npmjs.com/package/slashify WEB
https://www.npmjs.com/package/slashify

Frequently Asked Questions

What is CVE-2021-3189?
CVE-2021-3189 is a security vulnerability in Slashify involving Open redirect in Slashify under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Slashify versions are affected?
Affected versions include releases prior to current release patches across affected packages: slashify.
What version fixes CVE-2021-3189?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is slashify affected?
Yes, slashify is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-3189?
CVE-2021-3189 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2021-3189?
CVE-2021-3189 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check npm dependencies for CVE-2021-3189?
Run the dependency tree command: 'npm ls slashify'. 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-f4hq-453j-p95f",
  "modified" : "2022-05-26T20:40:57Z",
  "published" : "2021-02-05T20:43:34Z",
  "aliases" : [ "CVE-2021-3189" ],
  "summary" : "Open redirect in Slashify",
  "details" : "The package is an Express middleware that normalises routes by stripping any final slash, redirecting, for example, `bookings/latest/` to `bookings/latest`. However, it does not validate the path it redirects to in any way. In particular, if the path starts with two slashes (or two backslashes, or a slash and a backslash, etc.) it may redirect to a different domain.\n\nConsider the [example from the docs](https://www.npmjs.com/package/slashify#usage). Assume we have run it and started a server on `localhost:3000`, then visiting `localhost:3000///github.com/` redirects you to https://github.com.\n\n## Recommendation\n\nThis vulnerability is currently un-patched in the `slashify` package so there is no known safe version of this package. Discontinuing use of `slashify` is recommended.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "slashify"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3189"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/divshot/slashify"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20210401-0004"
  }, {
    "type" : "ADVISORY",
    "url" : "https://securitylab.github.com/advisories/GHSL-2020-199-open-redirect-slashify"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/slashify"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-02-05T20:42:47Z",
    "nvd_published_at" : "2021-02-19T23:15:00Z"
  }
}