CVE-2026-55087
CVE-2026-55087 · Etherpad: x-proxy-path header reflected into admin HTML/JS/CSS (cache-poisoning XSS) and concatenated into redirect (open-redirect)
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad uses the attacker-controlled x-proxy-path request header in src/node/hooks/express/admin.ts when substituting paths into HTML, JavaScript, and CSS under /admin without sanitization, Vary: x-proxy-path, or Cache-Control: private, no-store. A shared proxy or CDN can cache the resulting response and serve attacker-injected script to an administrator. In src/node/hooks/express/specialpages.ts, version 3.0.0 also accepts a protocol-relative x-proxy-path value when constructing the /p/:pad/timeslider redirect, allowing redirection to an attacker-controlled host. The issues are exploitable when the deployment permits client-supplied x-proxy-path headers to reach Etherpad. This issue is fixed in version 3.1.0.
CVSS 6.1 · Medium · EPSS 0.6% · Public exploit · Fix available
- Published
- Updated
Stack: node
Affected products and versions
etherpad
- Versions
- >= 2.1.0, < 3.1.0: Affected
No fix published
ep_etherpad-lite npm
- Affected ranges
- SEMVER: ≥ 2.1.0, < 3.1.0
Update to 3.1.0