CVE-2021-33829

mediumpriority · track · 25EPSS 0.032 · 88 %ileDEEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
3.19% (88th) EPSS
CVSS 4.3 · medium
Is it mine?
25 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.1
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9
v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 2.7
v3.16.1mediumAV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nsecondary · FSTEC (BDU) RU
v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nsecondary · OSV
v3.16mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:Fsecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimaryCWE-79USCWE-79US
03

affected products (25)

Products and version ranges known to be affected.

showing 20 of 25
04

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2024-0234OTRS: Mehrere SchwachstellenDeutsch2024-01-28csaf · cert_bundDE

    Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in OTRS ausnutzen, um Informationen offenzulegen, Sicherheitsmaßnahmen zu umgehen oder einen Cross Site Scripting Angriff durchzuführen.

  • GHSA-rgx6-rjj4-c388ckeditor4 vulnerable to cross-site scripting2021-06-21ghsa · osvUS

    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.

  • BIT-drupal-2021-338292024-03-06vendor · osvUS

    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.

  • DRUPAL-CORE-2021-0032021-05-26vendor · osvUS

    **Update: 2021-06-11: Added CVE-2021-33829 identifier** Drupal core uses the third-party CKEditor library. This library has an error in parsing HTML that could lead to an XSS attack. CKEditor 4.16.1 and later include the fix. Update: 2021-06-11: More details are available on [CKEditor's blog](https://ckeditor.com/blog/ckeditor-4.16.1-with-accessibility-enhancements/#improvements-for-comments-in-html-parser). Users of the CKEditor library via means other than Drupal core should update their 3rd party code (e.g. the WYSIWYG module for Drupal 7). The Drupal Security Team policy is not to alert for issues affecting 3rd party libraries unless those are shipped with Drupal core. See [DRUPAL-SA-PSA-2016-004 for more details](https://www.drupal.org/psa-2016-004). This issue is mitigated by the fact that it only affects sites with CKEditor enabled.

05

also known as (7)

Other names and identifiers for this entity.

06

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bduosvnvdcert_bundNVDCVE.orgMITRE
published 2021-06-09modified 2026-06-17
08

references (24)

External citations — patches, advisories, analysis.

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