CVE-2021-23509: Json ptr Prototype Pollution Vulnerability

MODERATE
Advisory Identifier: GHSA-8gwj-8hxc-285w
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CVSS 5.6
CWE-1321 CWE-843
Published
Advisory Summary

CVE-2021-23509 is a MODERATE (CVSS 5.6) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Json ptr libraries in the npm ecosystem. The issue involves prototype pollution in json-ptr. Remediation is available by upgrading affected packages to version 3.0.0.

CVE-2021-23509 at a Glance

CVE Identifier CVE-2021-23509
GHSA Identifier GHSA-8gwj-8hxc-285w
Severity MODERATE
CVSS v3.1 Base Score 5.6
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Json ptr
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.6

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

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
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-2021-23509

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

json-ptr fixed: 3.0.0 
npm install json-ptr@3.0.0
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 json-ptr

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-23509, inspect your project dependencies using npm:

npm ls json-ptr

Analyze the terminal output to locate any version of Json ptr in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.0.0), your application is affected.

Note: The npm ls json-ptr 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 Json ptr, 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

This affects the package `json-ptr` before `3.0.0`. A type confusion vulnerability can lead to a bypass of CVE-2020-7766 when the user-provided keys used in the pointer parameter are arrays.

CVE-2021-23509 Affected Json ptr Versions

1 component(s)
Fixed Versions:
3.0.0
Product / Package Ecosystem Affected Versions Fixed Version
json-ptr
npm/json-ptr
npm
< 3.0.0
3.0.0

References

NVD — CVE-2021-23509 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23509
Json ptr Source Repository REPOSITORY
https://github.com/flitbit/json-ptr/pull/42
Security Fix Commit FIX COMMIT
https://github.com/flitbit/json-ptr/commit/5dc458fbad1c382a2e3ca6d62e66ede3d92849ca
Json ptr Source Repository REPOSITORY
https://github.com/flitbit/json-ptr
Json ptr Source Repository REPOSITORY
https://github.com/flitbit/json-ptr%23security-vulnerabilities-resolved
snyk.io/vuln/snyk-js-jsonpt... WEB
https://snyk.io/vuln/SNYK-JS-JSONPTR-1577291

Frequently Asked Questions

What is CVE-2021-23509?
CVE-2021-23509 is a security vulnerability in Json ptr involving Prototype Pollution in json-ptr under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Json ptr versions are affected?
Affected versions include releases prior to 3.0.0 across affected packages: json-ptr.
What version fixes CVE-2021-23509?
Upgrading to 3.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is json-ptr affected?
Yes, json-ptr is affected in releases prior to 3.0.0. Upgrade your dependency to 3.0.0 or later.
What is the CVSS score of CVE-2021-23509?
CVE-2021-23509 has a CVSS v3.1 base score of 5.6 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2021-23509?
CVE-2021-23509 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-2021-23509?
Run the dependency tree command: 'npm ls json-ptr'. 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-8gwj-8hxc-285w",
  "modified" : "2021-11-08T17:43:16Z",
  "published" : "2021-11-08T17:43:27Z",
  "aliases" : [ "CVE-2021-23509" ],
  "summary" : "Prototype Pollution in json-ptr",
  "details" : "This affects the package `json-ptr` before `3.0.0`. A type confusion vulnerability can lead to a bypass of CVE-2020-7766 when the user-provided keys used in the pointer parameter are arrays.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "json-ptr"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23509"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flitbit/json-ptr/pull/42"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flitbit/json-ptr/commit/5dc458fbad1c382a2e3ca6d62e66ede3d92849ca"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/flitbit/json-ptr"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/flitbit/json-ptr%23security-vulnerabilities-resolved"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-JSONPTR-1577291"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321", "CWE-843" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-11-04T16:56:49Z",
    "nvd_published_at" : "2021-11-03T18:15:00Z"
  }
}