Vulnerabilities in pkg:npm/class-transformer

PACKAGE
Advisory Identifier: GHSA-6gp3-h3jj-prx4
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Advisory Summary

CVE-2020-7637 is a MODERATE (CVSS 5.3) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Class transformer libraries in the npm ecosystem. The issue involves prototype pollution in class-transformer. Remediation is available by upgrading affected packages to version 0.3.1.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/class-transformer

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/class-transformer. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-6gp3-h3jj-prx4 CVE-2020-7637 MODERATE Prototype pollution in class-transformer

CVE-2020-7637 at a Glance

CVE Identifier CVE-2020-7637
GHSA Identifier GHSA-6gp3-h3jj-prx4
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Class transformer
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

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:N/I:L/A:N).

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 Low (I:L)
Availability None (A:N)

How to Fix CVE-2020-7637

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

class-transformer fixed: 0.3.1 
npm install class-transformer@0.3.1
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 class-transformer

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2020-7637, inspect your project dependencies using npm:

npm ls class-transformer

Analyze the terminal output to locate any version of Class transformer in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.3.1), your application is affected.

Note: The npm ls class-transformer 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 Class transformer, 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

class-transformer through 0.2.3 is vulnerable to Prototype Pollution. The 'classToPlainFromExist' function could be tricked into adding or modifying properties of 'Object.prototype' using a '__proto__' payload.

CVE-2020-7637 Affected Class transformer Versions

1 component(s)
Fixed Versions:
0.3.1
Product / Package Ecosystem Affected Versions Fixed Version
class-transformer
npm/class-transformer
npm
< 0.3.1
0.3.1

References

NVD — CVE-2020-7637 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-7637
Security Fix Commit FIX COMMIT
https://github.com/typestack/class-transformer/commit/8f04eb9db02de708f1a20f6f2d2bb309b2fed01e
Class transformer Source Repository REPOSITORY
https://github.com/typestack/class-transformer
Class transformer Source Repository REPOSITORY
https://github.com/typestack/class-transformer/blob/a650d9f490573443f62508bc063b857bcd5e2525/src/ClassTransformer.ts#L29-L31,
snyk.io/vuln/snyk-js-classt... WEB
https://snyk.io/vuln/SNYK-JS-CLASSTRANSFORMER-564431

Frequently Asked Questions

What is CVE-2020-7637?
CVE-2020-7637 is a security vulnerability in Class transformer involving Prototype pollution in class-transformer under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Class transformer versions are affected?
Affected versions include releases prior to 0.3.1 across affected packages: class-transformer.
What version fixes CVE-2020-7637?
Upgrading to 0.3.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is class-transformer affected?
Yes, class-transformer is affected in releases prior to 0.3.1. Upgrade your dependency to 0.3.1 or later.
What is the CVSS score of CVE-2020-7637?
CVE-2020-7637 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2020-7637?
CVE-2020-7637 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-2020-7637?
Run the dependency tree command: 'npm ls class-transformer'. 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-6gp3-h3jj-prx4",
  "modified" : "2022-04-28T17:58:13Z",
  "published" : "2020-04-07T15:47:40Z",
  "aliases" : [ "CVE-2020-7637" ],
  "summary" : "Prototype pollution in class-transformer",
  "details" : "class-transformer through 0.2.3 is vulnerable to Prototype Pollution. The 'classToPlainFromExist' function could be tricked into adding or modifying properties of 'Object.prototype' using a '__proto__' payload.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "class-transformer"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.3.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-7637"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/typestack/class-transformer/commit/8f04eb9db02de708f1a20f6f2d2bb309b2fed01e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/typestack/class-transformer"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/typestack/class-transformer/blob/a650d9f490573443f62508bc063b857bcd5e2525/src/ClassTransformer.ts#L29-L31,"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-CLASSTRANSFORMER-564431"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321", "CWE-915" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-04-07T15:46:31Z",
    "nvd_published_at" : "2020-04-06T13:15:00Z"
  }
}