# CVE-2026-116688: CKEditor: Cross-site scripting (XSS) in the engine package


- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** GHSA-rh54-vffm-5fvp, UBUNTU-CVE-2026-116688

## What is CVE-2026-116688?

CVE-2026-116688 is a high-severity vulnerability in ckeditor5, published on 27 Oct 2026. 

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-116688?

8 open source packages ship an affected version, including @ckeditor/ckeditor5-engine and ckeditor5.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@ckeditor/ckeditor5-engine` | npm | From 45.0.0 | 47.7.4 |
| `@ckeditor/ckeditor5-engine` | npm | From 45.0.0 | 47.7.4 |
| `@ckeditor/ckeditor5-engine` | npm | From 48.0.0 | 48.5.1 |
| `@ckeditor/ckeditor5-engine` | npm | From 48.0.0 | 48.5.1 |
| `ckeditor5` | npm | From 45.0.0 | 47.7.4 |
| `ckeditor5` | npm | From 45.0.0 | 47.7.4 |
| `ckeditor5` | npm | From 48.0.0 | 48.5.1 |
| `ckeditor5` | npm | From 48.0.0 | 48.5.1 |

## How do I fix CVE-2026-116688?

Upgrade @ckeditor/ckeditor5-engine to a fixed version for your release line: 47.7.4 or 48.5.1.

## Is CVE-2026-116688 being exploited?

There is no known exploitation of CVE-2026-116688 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116688 and fix it if it is affected.

What it is: CVE-2026-116688 is a high-severity vulnerability in ckeditor5, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116688 in the wild and no public exploit code.

Affected packages and fixed versions:
- @ckeditor/ckeditor5-engine (npm): affected from 45.0.0; fixed in 47.7.4
- @ckeditor/ckeditor5-engine (npm): affected from 45.0.0; fixed in 47.7.4
- @ckeditor/ckeditor5-engine (npm): affected from 48.0.0; fixed in 48.5.1
- @ckeditor/ckeditor5-engine (npm): affected from 48.0.0; fixed in 48.5.1
- ckeditor5 (npm): affected from 45.0.0; fixed in 47.7.4
- ckeditor5 (npm): affected from 45.0.0; fixed in 47.7.4
- ckeditor5 (npm): affected from 48.0.0; fixed in 48.5.1
- ckeditor5 (npm): affected from 48.0.0; fixed in 48.5.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-116688/ (Markdown: https://insights.sbomify.com/CVE-2026-116688/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116688
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116688
- OSV: https://osv.dev/vulnerability/CVE-2026-116688

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-116688/
Summaries are generated and may contain mistakes; the official description above is the record.