CVE-2021-41164: Ckeditor4 Advanced Content Filter (ACF) Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-pvmx-g8h5-cprj
Share
CVSS 8.2
CWE-79
Published
Advisory Summary

CVE-2021-41164 is a HIGH (CVSS 8.2) advanced content filter (acf) vulnerability vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Ckeditor4 libraries in the npm ecosystem. The issue involves advanced content filter (acf) vulnerability allowing to execute javascript code using malformed html. Remediation is available by upgrading affected packages to version 4.17.0.

CVE-2021-41164 at a Glance

CVE Identifier CVE-2021-41164
GHSA Identifier GHSA-pvmx-g8h5-cprj
Severity HIGH
CVSS v3.1 Base Score 8.2
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Ckeditor4
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 8.2

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2021-41164

To remediate this vulnerability, upgrade all affected Ckeditor4 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ckeditor4 fixed: 4.17.0 
npm install ckeditor4@4.17.0
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 ckeditor4

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-41164, inspect your project dependencies using npm:

npm ls ckeditor4

Analyze the terminal output to locate any version of Ckeditor4 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.17.0), your application is affected.

Note: The npm ls ckeditor4 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 Ckeditor4, 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

### Affected packages The vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. ### Impact A potential vulnerability has been discovered in CKEditor 4 Advanced Content Filter (ACF) core module. The vulnerability allowed to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code. It affects all users using the CKEditor 4 at version < 4.17.0. ### Patches The problem has been recognized and patched. The fix will be available in version 4.17.0. ### For more information Email us at security@cksource.com if you have any questions or comments about this advisory. ### Acknowledgements The CKEditor 4 team would like to thank Maurice Dauer ([laytonctf](https://twitter.com/laytonctf)) for recognizing and reporting this vulnerability.

CVE-2021-41164 Affected Ckeditor4 Versions

1 component(s)
Fixed Versions:
4.17.0
Product / Package Ecosystem Affected Versions Fixed Version
ckeditor4
npm/ckeditor4
npm
< 4.17.0
4.17.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-pvmx-g8h5-cprj
NVD — CVE-2021-41164 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-41164
Ckeditor4 Source Repository REPOSITORY
https://github.com/ckeditor/ckeditor4
Ckeditor4 Source Repository REPOSITORY
https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-417
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VR76VBN5GW5QUBJFHVXRX36UZ6YTCMW6
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WOZGMCYDB2OKKULFXZKM6V7JJW4ZZHJP
www.drupal.org/sa-core-2021-011 WEB
https://www.drupal.org/sa-core-2021-011
Ckeditor4 Security Information SECURITY
https://www.oracle.com/security-alerts/cpuapr2022.html
Ckeditor4 Security Information SECURITY
https://www.oracle.com/security-alerts/cpujan2022.html
Ckeditor4 Security Information SECURITY
https://www.oracle.com/security-alerts/cpujul2022.html

Frequently Asked Questions

What is CVE-2021-41164?
CVE-2021-41164 is a security vulnerability in Ckeditor4 involving Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Ckeditor4 versions are affected?
Affected versions include releases prior to 4.17.0 across affected packages: ckeditor4.
What version fixes CVE-2021-41164?
Upgrading to 4.17.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ckeditor4 affected?
Yes, ckeditor4 is affected in releases prior to 4.17.0. Upgrade your dependency to 4.17.0 or later.
What is the CVSS score of CVE-2021-41164?
CVE-2021-41164 has a CVSS v3.1 base score of 8.2 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L.
What CWE is associated with CVE-2021-41164?
CVE-2021-41164 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-2021-41164?
Run the dependency tree command: 'npm ls ckeditor4'. 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-pvmx-g8h5-cprj",
  "modified" : "2022-02-08T20:39:22Z",
  "published" : "2021-11-17T21:55:10Z",
  "aliases" : [ "CVE-2021-41164" ],
  "summary" : "Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML",
  "details" : "### Affected packages\nThe vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4.\n\n### Impact\nA potential vulnerability has been discovered in CKEditor 4 Advanced Content Filter (ACF) core module. The vulnerability allowed to inject malformed HTML bypassing content sanitization, which could result in executing JavaScript code. It affects all users using the CKEditor 4 at version < 4.17.0.\n\n### Patches\nThe problem has been recognized and patched. The fix will be available in version 4.17.0.\n\n### For more information\nEmail us at security@cksource.com if you have any questions or comments about this advisory.\n\n### Acknowledgements\nThe CKEditor 4 team would like to thank Maurice Dauer ([laytonctf](https://twitter.com/laytonctf)) for recognizing and reporting this vulnerability.\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "ckeditor4"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.17.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ckeditor/ckeditor4/security/advisories/GHSA-pvmx-g8h5-cprj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-41164"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ckeditor/ckeditor4"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ckeditor/ckeditor4/blob/major/CHANGES.md#ckeditor-417"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VR76VBN5GW5QUBJFHVXRX36UZ6YTCMW6"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WOZGMCYDB2OKKULFXZKM6V7JJW4ZZHJP"
  }, {
    "type" : "WEB",
    "url" : "https://www.drupal.org/sa-core-2021-011"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpuapr2022.html"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpujan2022.html"
  }, {
    "type" : "WEB",
    "url" : "https://www.oracle.com/security-alerts/cpujul2022.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-11-17T19:56:22Z",
    "nvd_published_at" : "2021-11-17T19:15:00Z"
  }
}