Open redirect in etherpad
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Spoofing, Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-601 and CWE-79.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| ether | etherpad | 2.1.0 to before 3.1.0 | 3.1.0 | Patch available | CNA |
| — | ep_etherpad-lite (npm) | 2.1.0 to before 3.1.0 | 3.1.0 | Patch available | GHSA-fjgc-3mj7-8rg8 |
- etherpad Vendorether Affected 2.1.0 to before 3.1.0 Fixed in 3.1.0 Patch available CNA
- ep_etherpad-lite (npm) Vendor— Affected 2.1.0 to before 3.1.0 Fixed in 3.1.0 Patch available GHSA-fjgc-3mj7-8rg8
Remediation
- Fix · CNA etherpad (ether) Fixed in 3.1.0
- Fix · GHSA-fjgc-3mj7-8rg8 ep_etherpad-lite (npm) Fixed in 3.1.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-55087
- 2026-10-03 Alias added: GHSA-fjgc-3mj7-8rg8
References
Other 9
- https://github.com/ether/etherpad/security/advisories/GHSA-fjgc-3mj7-8rg8
- https://github.com/ether/etherpad/pull/7784
- https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996
- https://github.com/ether/etherpad/tree/3.1.0
- https://github.com/ether/etherpad/pull/6399
- https://github.com/ether/etherpad/pull/7710
- https://github.com/ether/etherpad/commit/451bd9c3ebb0dded99dd0ff21811ee00e0940c29
- https://github.com/ether/etherpad/commit/63e9b2d4eb303cd341022591bdf9484584db36e3
- https://github.com/ether/etherpad
More ether vulnerabilities
- TI-2026-39793 Etherpad: JWT `admin` claim presence-only check lets non-admin OAuth users invoke every Etherpad HTTP API endpoint CVSS 3.1CRITICAL 9.9
- TI-2026-39789 Etherpad: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in etherpad-lite CVSS 3.1CRITICAL 9.6
- TI-2026-39790 Link following in etherpad CVSS 3.1MEDIUM 4.2
- TI-2009-04910 Session fixation in ether Catalyst::Plugin::Authentication CVSS 3.1CRITICAL 9.1
- TI-2025-27313 Catalyst::Authentication::Credential::HTTP versions 1.018 and earlier for Perl use insecurely generated nonces CVSS 3.1HIGH 8.6
- TI-2026-39792 Information disclosure in etherpad CVSS 3.1MEDIUM 6.8
Sources
- CVE-2026-55087 · CVE Program
- CVE-2026-55087 · NVD
- FIRST EPSS
- GHSA-fjgc-3mj7-8rg8 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences