CVE-2020-7742: Simpl schema Prototype Pollution Vulnerability

HIGH
Advisory Identifier: GHSA-9mx2-prfp-8hqp
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CVSS 7.5
CWE-1321
Published
Advisory Summary

CVE-2020-7742 is a HIGH (CVSS 7.5) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Simpl schema libraries in the npm ecosystem. The issue involves prototype pollution in simpl-schema. Remediation is available by upgrading affected packages to version 1.10.2.

CVE-2020-7742 at a Glance

CVE Identifier CVE-2020-7742
GHSA Identifier GHSA-9mx2-prfp-8hqp
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Simpl schema
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

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:N/I:N/A:H).

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 None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2020-7742

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

simpl-schema fixed: 1.10.2 
npm install simpl-schema@1.10.2
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 simpl-schema

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2020-7742, inspect your project dependencies using npm:

npm ls simpl-schema

Analyze the terminal output to locate any version of Simpl schema in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.10.2), your application is affected.

Note: The npm ls simpl-schema 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 Simpl schema, 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 simpl-schema before 1.10.2. Attacker controlled input into a schema could result in remote code execution within the scope of the surrounding application.

CVE-2020-7742 Affected Simpl schema Versions

1 component(s)
Fixed Versions:
1.10.2
Product / Package Ecosystem Affected Versions Fixed Version
simpl-schema
npm/simpl-schema
npm
< 1.10.2
1.10.2

References

NVD — CVE-2020-7742 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-7742
Security Fix Commit FIX COMMIT
https://github.com/longshotlabs/simpl-schema/commit/50128841fa7fc2d137c36a397054279144caea3d
Simpl schema Release RELEASE
https://github.com/longshotlabs/simpl-schema/releases/tag/1.10.2
snyk.io/vuln/snyk-js-simpls... WEB
https://snyk.io/vuln/SNYK-JS-SIMPLSCHEMA-1016157

Frequently Asked Questions

What is CVE-2020-7742?
CVE-2020-7742 is a security vulnerability in Simpl schema involving Prototype Pollution in simpl-schema under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Simpl schema versions are affected?
Affected versions include releases prior to 1.10.2 across affected packages: simpl-schema.
What version fixes CVE-2020-7742?
Upgrading to 1.10.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is simpl-schema affected?
Yes, simpl-schema is affected in releases prior to 1.10.2. Upgrade your dependency to 1.10.2 or later.
What is the CVSS score of CVE-2020-7742?
CVE-2020-7742 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-7742?
CVE-2020-7742 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-2020-7742?
Run the dependency tree command: 'npm ls simpl-schema'. 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-9mx2-prfp-8hqp",
  "modified" : "2021-04-21T20:37:29Z",
  "published" : "2021-05-10T18:38:47Z",
  "aliases" : [ "CVE-2020-7742" ],
  "summary" : "Prototype Pollution in simpl-schema",
  "details" : "This affects the package simpl-schema before 1.10.2. Attacker controlled input into a schema could result in remote code execution within the scope of the surrounding application.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "simpl-schema"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.10.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-7742"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/longshotlabs/simpl-schema/commit/50128841fa7fc2d137c36a397054279144caea3d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/longshotlabs/simpl-schema/releases/tag/1.10.2"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-SIMPLSCHEMA-1016157"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-04-21T20:37:29Z",
    "nvd_published_at" : "2020-10-07T09:15:00Z"
  }
}