CVE-2021-33829

MEDIUM NUCLEI

CKEditor 4.14.0-4.16.0 - Cross-Site Scripting via HTML Comment Parsing

Title source: llm

Exploitation Summary

CVE-2021-33829 has a Nuclei detection template available — see the Nuclei card below for the Shodan/FOFA recon queries.

Description

A cross-site scripting (XSS) vulnerability in the HTML Data Processor in CKEditor 4 4.14.0 through 4.16.x before 4.16.1 allows remote attackers to inject executable JavaScript code through a crafted comment because --!> is mishandled.

Nuclei Templates (1)

Drupal 7 CKEditor XSS

MEDIUMVERIFIEDby 0x_Akoko

Shodan: cpe:"cpe:2.3:a:ckeditor:ckeditor"

References (6)

Core 6

Core References

Patch, Third Party Advisory x_refsource_confirm

https://www.drupal.org/sa-core-2021-003

Patch, Release Notes, Vendor Advisory x_refsource_misc

https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser

Mailing List, Third Party Advisory vendor-advisory x_refsource_fedora

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NYA354LJP47KCVJMTUO77ZCX3ZK42G3T/

Mailing List, Third Party Advisory vendor-advisory x_refsource_fedora

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UVOYN2WKDPLKCNILIGEZM236ABQASLGW/

Mailing List, Third Party Advisory vendor-advisory x_refsource_fedora

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAGNWHFIQAVCP537KFFS2A2GDG66J7XD/

Mailing List, Third Party Advisory mailing-list x_refsource_mlist

https://lists.debian.org/debian-lts-announce/2021/11/msg00007.html

Scores

CVSS v3 6.1

EPSS 0.0319

EPSS Percentile 86.4%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Details

CWE

CWE-79

Status published

Products (9)

ckeditor/ckeditor 4.14.0 - 4.16.1

debian/debian_linux 9.0

drupal/core 7.0.0 - 7.80Packagist

drupal/drupal 7.0.0 - 7.80Packagist

drupal/drupal 8.9.0 - 8.9.16

fedoraproject/fedora 33

fedoraproject/fedora 34

fedoraproject/fedora 35

npm/ckeditor4 4.14.0 - 4.16.1npm

Published Jun 09, 2021

Tracked Since Feb 18, 2026