Cross-Site Scripting (XSS) in tinymce (CVE-2020-17480)
Summary
Cross-site scripting in tinymce (CVE-2020-17480). Risk of unauthorized operations or information disclosure. Exploitable via paste. Mitigation: upgrade to 5.1.4 or later.
Original description
The description as published by the source.
Impact
A cross-site scripting (XSS) vulnerability was discovered in: the core parser, paste and visualchars plugins. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor via the clipboard or APIs. This impacts all users who are using TinyMCE 4.9.6 or lower and TinyMCE 5.1.3 or lower.
Patches
This vulnerability has been patched in TinyMCE 4.9.7 and 5.1.4 by improved parser logic and HTML sanitization.
Workarounds
The workarounds available are:
- disable the impacted plugins
- manually sanitize the content using the
BeforeSetContentevent (see below) - upgrade to either TinyMCE 4.9.7 or TinyMCE 5.1.4
Example: Manually sanitize content
editor.on('BeforeSetContent', function(e) {
var sanitizedContent = ...; // Manually sanitize content here
e.content = sanitizedContent;
});
Acknowledgements
Tiny Technologies would like to thank Michał Bentkowski for discovering this vulnerability.
References
https://www.tiny.cloud/docs/release-notes/release-notes514/#securityfixes
For more information
If you have any questions or comments about this advisory:
- Open an issue in the TinyMCE repo
- Email us at infosec@tiny.cloud
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-2020-17480 has been found in tinymce.
Attackers can target a specific entry point like paste over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade tinymce to 5.1.4 or later.
If unsure, ask your IT team or search "tinymce CVE-2020-17480" on the vendor's site.
CVE-2020-17480 (tinymce) — CWE-79
Attack surface: paste / visualchars / BeforeSetContent
Patched: 5.1.4 — 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.
Cross-site scripting (XSS) (CWE-79) exists in tinymce. Attackers reach the vulnerable code path via paste.
Check the vendor advisory for the affected versions of tinymce. Attack surface: paste / visualchars / BeforeSetContent.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 5.1.4.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'tinymce' . 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
-
1Identify exposure identify
grep -r 'tinymce' . | 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
tinymceを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade tinymce to 5.1.4ステージング環境で 5.1.4 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。
-
3Post-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
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web portswigger.net
- web tiny.cloud