# CKEditor: Cross-site scripting (XSS) in the engine package Advisory record · `GHSA-v6mg-96c6-gmpq` - **Identifiers:** `GHSA-v6mg-96c6-gmpq` · `CVE-2026-116687` - **State:** Confirmed - **Severity:** CVSS 3.1 Low - **Critical:** No - **Weakness (CWE):** [CWE-79](https://cwe.mitre.org/data/definitions/79.html) - **Tags:** [Cross-site scripting (XSS)](https://agentprime.io/advisories/tag/xss.md) - **Published:** 27 Oct 2026 - **Updated:** 27 Oct 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 27 Oct 2026, 21:05 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `ckeditor5` (npm): affected `>=29.0.0, <47.7.4 || >=48.0.0, <48.5.1`; fixed in `47.7.4`, `48.5.1` - `@ckeditor/ckeditor5-engine` (npm): affected `>=29.0.0, <47.7.4 || >=48.0.0, <48.5.1`; fixed in `47.7.4`, `48.5.1` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > The ckeditor5 and @ckeditor/ckeditor5-engine npm packages, versions from 29.0.0 up to but not including 47.7.4, and from 48.0.0 up to but not including 48.5.1, contain a cross-site scripting flaw in the CKEditor 5 engine. It is triggered by inserting specially crafted markup, and only when General HTML Support is enabled and configured to allow the affected HTML content; the source says JavaScript could then run in a browser context isolated from the embedding application's origin. Upgrade to version 47.7.4 (LTS) or 48.5.1 or later. Written 31 Oct 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - 3.1 Low, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0025, the 16th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 27 Oct 2026, 19:33 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-116687) - 27 Oct 2026, 20:17 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-116687) - 31 Oct 2026, 13:33 UTC: First seen by agentprime - 31 Oct 2026, 13:33 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-v6mg-96c6-gmpq) ## Sources - [GitHub Advisory Database: GHSA-v6mg-96c6-gmpq](https://github.com/advisories/GHSA-v6mg-96c6-gmpq) - [OSV: GHSA-v6mg-96c6-gmpq](https://osv.dev/vulnerability/GHSA-v6mg-96c6-gmpq) - - - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .