CVE-2026-116688: XSS (CVSS 8.1)

Description

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 45.0.0 until 47.7.4 and 48.5.1, the engine uses a vulnerable es-toolkit version whose prototype-pollution behavior can be reached while CKEditor processes incoming style attribute values. Crafted editor content can thereby cause unauthorized JavaScript execution in the browser. This issue is fixed in versions 47.7.4 and 48.5.1.

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CVSS v3.1 Score

8.1

HIGH

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

EPSS — Exploit Prediction

0.0050

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/ckeditor/ckeditor5/commit/4d9c5bb34f63cd956d15ccafbe584e14280c86a0 https://github.com/ckeditor/ckeditor5/commit/a750e38635db6a18c5b11599c09f4fd702850423 https://github.com/ckeditor/ckeditor5/releases/tag/v47.7.4 https://github.com/ckeditor/ckeditor5/releases/tag/v48.5.1 https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-rh54-vffm-5fvp

Frequently Asked Questions

What is CVE-2026-116688? +

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. From 45.0.0 until 47.7.4 and 48.5.1, the engine uses a vulnerable es-toolkit version whose prototype-pollution behavior can be reached while CKEditor processes incoming style attribute values. Crafted editor content can thereby cause unauthorized JavaScript execution in the browser. This issue is fixed in versions 47.7.4 and 48.5.1. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-116688? +

CVE-2026-116688 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0050, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-116688? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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