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Clipboard feature vulnerability allowing to inject arbitrary HTML into the editor using paste functionality

Moderate severity GitHub Reviewed Published Aug 12, 2021 in ckeditor/ckeditor4 • Updated Feb 1, 2023

Package

npm ckeditor4 (npm)

Affected versions

>= 4.5.2, < 4.16.2

Patched versions

4.16.2

Description

Affected packages

The vulnerability has been discovered in clipboard plugin. All plugins with clipboard plugin dependency are affected:

Impact

A potential vulnerability has been discovered in CKEditor 4 Clipboard package. The vulnerability allowed to abuse paste functionality using malformed HTML, which could result in injecting arbitrary HTML into the editor. It affects all users using the CKEditor 4 plugins listed above at version >= 4.5.2.

Patches

The problem has been recognized and patched. The fix will be available in version 4.16.2.

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 Anton Subbotin (skavans) for recognizing and reporting this vulnerability.

References

@jacekbogdanski jacekbogdanski published to ckeditor/ckeditor4 Aug 12, 2021
Published by the National Vulnerability Database Aug 12, 2021
Reviewed Aug 23, 2021
Published to the GitHub Advisory Database Aug 23, 2021
Last updated Feb 1, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

EPSS score

0.163%
(53rd percentile)

Weaknesses

CVE ID

CVE-2021-32809

GHSA ID

GHSA-7889-rm5j-hpgg

Source code

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