CVE-2020-26302: Is js Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-pvrw-g6fx-mcx2
Share
CVSS 7.5
CWE-400 CWE-1333
Published
Advisory Summary

CVE-2020-26302 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Is js libraries in the npm ecosystem. The issue involves is_js vulnerable to regular expression denial of service. Remediation is available in the latest vendor maintenance releases.

CVE-2020-26302 at a Glance

CVE Identifier CVE-2020-26302
GHSA Identifier GHSA-pvrw-g6fx-mcx2
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Is js
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-2020-26302

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

is_js fixed: Latest secure release 
npm install is_js@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 is_js

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2020-26302, inspect your project dependencies using npm:

npm ls is_js

Analyze the terminal output to locate any version of Is js 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 is_js 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-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Is js, 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

is.js is a general-purpose check library. Versions 0.9.0 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). is.js uses a regex copy-pasted from a gist to validate URLs. Trying to validate a malicious string can cause the regex to loop "forever." This vulnerability was found using a CodeQL query which identifies inefficient regular expressions. is.js has no patch for this issue.

CVE-2020-26302 Affected Is js Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
is_js
npm/is_js
npm
≤ 0.9.0

References

NVD — CVE-2020-26302 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26302
Is js Source Repository REPOSITORY
https://github.com/arasatasaygin/is.js/issues/320
Is js Source Repository REPOSITORY
https://github.com/arasatasaygin/is.js
GitHub Advisory / Wiki ADVISORY
https://securitylab.github.com/advisories/GHSL-2020-295-redos-is.js

Frequently Asked Questions

What is CVE-2020-26302?
CVE-2020-26302 is a security vulnerability in Is js involving is_js vulnerable to Regular Expression Denial of Service under CWE-400: Uncontrolled Resource Consumption.
Which Is js versions are affected?
Affected versions include releases prior to current release patches across affected packages: is_js.
What version fixes CVE-2020-26302?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is is_js affected?
Yes, is_js 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-2020-26302?
CVE-2020-26302 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-2020-26302?
CVE-2020-26302 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2020-26302?
Run the dependency tree command: 'npm ls is_js'. 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-pvrw-g6fx-mcx2",
  "modified" : "2023-07-06T21:46:34Z",
  "published" : "2023-07-06T19:24:05Z",
  "aliases" : [ "CVE-2020-26302" ],
  "summary" : "is_js vulnerable to Regular Expression Denial of Service",
  "details" : "is.js is a general-purpose check library. Versions 0.9.0 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). is.js uses a regex copy-pasted from a gist to validate URLs. Trying to validate a malicious string can cause the regex to loop \"forever.\" This vulnerability was found using a CodeQL query which identifies inefficient regular expressions. is.js has no patch for this issue.",
  "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" : "is_js"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.9.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-26302"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/arasatasaygin/is.js/issues/320"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/arasatasaygin/is.js"
  }, {
    "type" : "ADVISORY",
    "url" : "https://securitylab.github.com/advisories/GHSL-2020-295-redos-is.js"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333", "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-06T21:46:34Z",
    "nvd_published_at" : "2022-12-22T21:15:00Z"
  }
}