CVE-2021-41164
Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
CVE-2021-41164- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-2375
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
EUVD-2021-2375- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-pvmx-g8h5-cprj
Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML
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 [email protected] if you have any questions or comments about this advisory.
Acknowledgements
The CKEditor 4 team would like to thank Maurice Dauer (laytonctf) for recognizing and reporting this vulnerability.
- Record
GHSA-pvmx-g8h5-cprj- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
CVE-2021-41164- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
CVE-2021-41164- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-41164
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
DEBIAN-CVE-2021-41164- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-pvmx-g8h5-cprj
Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML
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 [email protected] if you have any questions or comments about this advisory.
Acknowledgements
The CKEditor 4 team would like to thank Maurice Dauer (laytonctf) for recognizing and reporting this vulnerability.
- Record
GHSA-pvmx-g8h5-cprj- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-41164
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
UBUNTU-CVE-2021-41164- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:L - CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVBIT-drupal-2021-41164 No score
Advanced Content Filter (ACF) vulnerability allowing to execute JavaScript code using malformed HTML
CKEditor4 is an open source WYSIWYG HTML editor. In affected versions a vulnerability has been discovered in the Advanced Content Filter (ACF) module and may affect all plugins used by CKEditor 4. 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. The problem has been recognized and patched. The fix will be available in version 4.17.0.
- Record
BIT-drupal-2021-41164- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ckeditor4npm |
before 4.17.0 | 4.17.0 |
drupalBitnami |
8.9.0 up to 8.9.20, 9.1.0 up to 9.1.14, 9.2.0 up to 9.2.9 | 8.9.209.1.149.2.9 |
ckeditorDebian:12 |
before 4.19.0+dfsg-1 | 4.19.0+dfsg-1 |
ckeditorUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 4.4.4+dfsg1-34.5.6+dfsg-14.5.7+dfsg-14.5.7+dfsg-24.5.7+dfsg-2ubuntu0.16.04.1~esm14.5.7+dfsg-2ubuntu0.16.04.1~esm24.5.7+dfsg-2ubuntu0.16.04.1~esm3 |
None known |
ldap-account-managerUbuntu:16.04:LTS |
All versions, plus listed versions 4.9-15.1-15.2-15.2-1ubuntu1 |
None known |
request-tracker4Ubuntu:16.04:LTS |
All versions, plus listed versions 4.2.11-24.2.12-34.2.12-44.2.12-5 |
None known |
ckeditorUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 4.5.7+dfsg-24.5.7+dfsg-2ubuntu0.18.04.14.5.7+dfsg-2ubuntu0.18.04.1+esm14.5.7+dfsg-2ubuntu0.18.04.1+esm2 |
None known |
ckeditor3Ubuntu:18.04:LTS |
All versions, plus listed versions 3.6.6.1+dfsg-1 |
None known |
ldap-account-managerUbuntu:18.04:LTS |
All versions, plus listed versions 5.7-16.1-16.2-1 |
None known |
request-tracker4Ubuntu:Pro:18.04:LTS |
All versions, plus listed versions 4.4.1-54.4.2-14.4.2-24.4.2-2ubuntu0.1~esm1 |
None known |
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| Package | Affected | Fixed |
|---|---|---|
ckeditorUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 4.11.1+dfsg-14.12.1+dfsg-14.12.1+dfsg-1ubuntu0.14.12.1+dfsg-1ubuntu0.1+esm14.12.1+dfsg-1ubuntu0.1+esm2 |
None known |
ckeditor3Ubuntu:20.04:LTS |
All versions, plus listed versions 3.6.6.1+dfsg-33.6.6.1+dfsg-4 |
None known |
ldap-account-managerUbuntu:20.04:LTS |
All versions, plus listed versions 6.7-1 |
None known |
request-tracker4Ubuntu:20.04:LTS |
All versions, plus listed versions 4.4.3-24.4.3-2+deb10u3build0.20.04.1 |
None known |
ckeditor3Ubuntu:22.04:LTS |
All versions, plus listed versions 3.6.6.1+dfsg-7 |
None known |
ldap-account-managerUbuntu:22.04:LTS |
All versions, plus listed versions 7.5-17.7-1 |
None known |
request-tracker4Ubuntu:22.04:LTS |
All versions, plus listed versions 4.4.4+dfsg-2ubuntu14.4.4+dfsg-2ubuntu1.22.04.1 |
None known |
ckeditorUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 4.16.0+dfsg-24.16.2+dfsg-14.16.2+dfsg-1ubuntu0.1~esm14.16.2+dfsg-1ubuntu0.1~esm2 |
None known |
ckeditor3Ubuntu:24.04:LTS |
All versions, plus listed versions 3.6.6.1+dfsg-7 |
None known |
ldap-account-managerUbuntu:24.04:LTS |
All versions, plus listed versions 8.3-18.5-1 |
None known |
request-tracker4Ubuntu:24.04:LTS |
All versions, plus listed versions 4.4.4+dfsg-2ubuntu14.4.4+dfsg-2ubuntu24.4.7+dfsg-1 |
None known |
ldap-account-managerUbuntu:25.10 |
All versions, plus listed versions 9.0-1 |
None known |
request-tracker4Ubuntu:25.10 |
All versions, plus listed versions 4.4.7+dfsg-4syncable1 |
None known |
ldap-account-managerUbuntu:26.04:LTS |
All versions, plus listed versions 9.0-19.0-1build1 |
None known |
request-tracker4Ubuntu:26.04:LTS |
All versions, plus listed versions 4.4.7+dfsg-4syncable1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41164 is a high vulnerability (CVSS 8.2) in Ckeditor, published November 17, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.35%, the 71st percentile. Fixed in ckeditor4 4.17.0.
References
github.com/ckeditor/ckeditor4/security/advisories/GHSA-pvmx-g8h5-cprj
oracle.com/security-alerts/cpujan2022.html
drupal.org/sa-core-2021-011
Show 10 moreShow less
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WOZGMCYDB2OKKULFXZKM6V7JJW4ZZHJP
nvd.nist.gov/vuln/detail/CVE-2021-41164
security-tracker.debian.org/tracker/CVE-2021-41164
ubuntu.com/security/CVE-2021-41164
cve.org/CVERecord?id=CVE-2021-41164