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CVE-2021-32809

Cross-Site Scripting (XSS) in ckeditor4 (CVE-2021-32809)

Summary

Cross-site scripting in ckeditor4 (CVE-2021-32809). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 4.16.2 or later.

Original description

The description as published by the source.

ckeditor is an open source WYSIWYG HTML editor with rich content support. 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. The problem has been recognized and patched. The fix will be available in version 4.16.2.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-32809 has been found in ckeditor4.
Risk of unauthorized operations or information disclosure.
What to do: upgrade ckeditor4 to 4.16.2 or later.
If unsure, ask your IT team or search "ckeditor4 CVE-2021-32809" on the vendor's site.

CVE-2021-32809 (ckeditor4) — CWE-79
Attack vector: remote (network-reachable)
Patched: 4.16.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

Cross-site scripting (XSS) (CWE-79) exists in ckeditor4.

📍 Affected scope

Check the vendor advisory for the affected versions of ckeditor4.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 4.16.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'ckeditor4' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'ckeditor4' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で ckeditor4 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade ckeditor4 to 4.16.2

    ステージング環境で 4.16.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

npm ckeditor4
[{"type":"SEMVER","events":[{"introduced":"4.5.2"},{"fixed":"4.16.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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