CVE-2021-23518: Cached path relative Prototype Pollution Vulnerability

HIGH
Advisory Identifier: GHSA-wg6g-ppvx-927h
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CVSS 7.3
CWE-1321
Published
Advisory Summary

CVE-2021-23518 is a HIGH (CVSS 7.3) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Cached path relative libraries in the npm ecosystem. The issue involves prototype pollution in cached-path-relative. Remediation is available by upgrading affected packages to version 1.1.0.

CVE-2021-23518 at a Glance

CVE Identifier CVE-2021-23518
GHSA Identifier GHSA-wg6g-ppvx-927h
Severity HIGH
CVSS v3.1 Base Score 7.3
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Cached path relative
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.3

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

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

How to Fix CVE-2021-23518

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

cached-path-relative fixed: 1.1.0 
npm install cached-path-relative@1.1.0
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 cached-path-relative

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-23518, inspect your project dependencies using npm:

npm ls cached-path-relative

Analyze the terminal output to locate any version of Cached path relative in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.1.0), your application is affected.

Note: The npm ls cached-path-relative 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-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Cached path relative, 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 cached-path-relative before 1.1.0 is vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. **Note:** This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-72573

CVE-2021-23518 Affected Cached path relative Versions

1 component(s)
Fixed Versions:
1.1.0
Product / Package Ecosystem Affected Versions Fixed Version
cached-path-relative
npm/cached-path-relative
npm
< 1.1.0
1.1.0

References

NVD — CVE-2021-23518 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23518
Security Fix Commit FIX COMMIT
https://github.com/ashaffer/cached-path-relative/commit/40c73bf70c58add5aec7d11e4f36b93d144bb760
Cached path relative Source Repository REPOSITORY
https://github.com/ashaffer/cached-path-relative
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2022/12/msg00006.html
snyk.io/vuln/snyk-java-orgw... WEB
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-2348246
snyk.io/vuln/snyk-js-cached... WEB
https://snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-2342653

Frequently Asked Questions

What is CVE-2021-23518?
CVE-2021-23518 is a security vulnerability in Cached path relative involving Prototype Pollution in cached-path-relative under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Cached path relative versions are affected?
Affected versions include releases prior to 1.1.0 across affected packages: cached-path-relative.
What version fixes CVE-2021-23518?
Upgrading to 1.1.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is cached-path-relative affected?
Yes, cached-path-relative is affected in releases prior to 1.1.0. Upgrade your dependency to 1.1.0 or later.
What is the CVSS score of CVE-2021-23518?
CVE-2021-23518 has a CVSS v3.1 base score of 7.3 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2021-23518?
CVE-2021-23518 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2021-23518?
Run the dependency tree command: 'npm ls cached-path-relative'. 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-wg6g-ppvx-927h",
  "modified" : "2022-01-27T14:26:40Z",
  "published" : "2022-01-27T14:27:53Z",
  "aliases" : [ "CVE-2021-23518" ],
  "summary" : "Prototype Pollution in cached-path-relative",
  "details" : "The package cached-path-relative before 1.1.0 is vulnerable to Prototype Pollution via the cache variable that is set as {} instead of Object.create(null) in the cachedPathRelative function, which allows access to the parent prototype properties when the object is used to create the cached relative path. When using the origin path as __proto__, the attribute of the object is accessed instead of a path. **Note:** This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-72573",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "cached-path-relative"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23518"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ashaffer/cached-path-relative/commit/40c73bf70c58add5aec7d11e4f36b93d144bb760"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ashaffer/cached-path-relative"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2022/12/msg00006.html"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-2348246"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-CACHEDPATHRELATIVE-2342653"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-01-24T23:03:02Z",
    "nvd_published_at" : "2022-01-21T20:15:00Z"
  }
}