CVE-2021-42648: Code server Cross Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-2gp3-6c9p-jp7w
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2021-42648 is a MODERATE (CVSS 6.1) cross site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Code server libraries in the npm ecosystem. The issue involves cross site scripting in code-server. Remediation is available by upgrading affected packages to version 3.12.0.

CVE-2021-42648 at a Glance

CVE Identifier CVE-2021-42648
GHSA Identifier GHSA-2gp3-6c9p-jp7w
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Code server
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.1

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

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

How to Fix CVE-2021-42648

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

code-server fixed: 3.12.0 
npm install code-server@3.12.0
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 code-server

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-42648, inspect your project dependencies using npm:

npm ls code-server

Analyze the terminal output to locate any version of Code server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.12.0), your application is affected.

Note: The npm ls code-server 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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Code server, 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

Cross-site scripting (XSS) vulnerability exists in Coder Code-Server before 3.12.0, allows attackers to execute arbitrary code via crafted URL.

CVE-2021-42648 Affected Code server Versions

1 component(s)
Fixed Versions:
3.12.0
Product / Package Ecosystem Affected Versions Fixed Version
code-server
npm/code-server
npm
< 3.12.0
3.12.0

References

NVD — CVE-2021-42648 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-42648
Code server Source Repository REPOSITORY
https://github.com/cdr/code-server/issues/4355
Code server Source Repository REPOSITORY
https://github.com/coder/code-server/pull/4430
Code server Source Repository REPOSITORY
https://github.com/coder/code-server

Frequently Asked Questions

What is CVE-2021-42648?
CVE-2021-42648 is a security vulnerability in Code server involving Cross site scripting in code-server under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Code server versions are affected?
Affected versions include releases prior to 3.12.0 across affected packages: code-server.
What version fixes CVE-2021-42648?
Upgrading to 3.12.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is code-server affected?
Yes, code-server is affected in releases prior to 3.12.0. Upgrade your dependency to 3.12.0 or later.
What is the CVSS score of CVE-2021-42648?
CVE-2021-42648 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2021-42648?
CVE-2021-42648 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check npm dependencies for CVE-2021-42648?
Run the dependency tree command: 'npm ls code-server'. 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-2gp3-6c9p-jp7w",
  "modified" : "2022-05-24T22:18:10Z",
  "published" : "2022-05-12T00:00:40Z",
  "aliases" : [ "CVE-2021-42648" ],
  "summary" : "Cross site scripting in code-server",
  "details" : "Cross-site scripting (XSS) vulnerability exists in Coder Code-Server before 3.12.0, allows attackers to execute arbitrary code via crafted URL.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "code-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.12.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-42648"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/cdr/code-server/issues/4355"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/coder/code-server/pull/4430"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/coder/code-server"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-05-24T22:18:10Z",
    "nvd_published_at" : "2022-05-11T18:15:00Z"
  }
}