---
id: CVE-2026-55089
title: Etherpad is a real-time collaborative editor
summary: >-
  Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0,
  Etherpad's src/node/handler/APIHandler.ts authorizes requests to /api/2/* in
  the authorization_code OAuth path by using requiredClaims with the admin
  claim. This check…
severity: critical
cvss: 9.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L'
cwe:
  - CWE-863
published: '2026-08-19'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:15:59.613'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55089'
references:
  - url: >-
      https://github.com/ether/etherpad/commit/8c6104c5d5daf41f0d454acc04d42dffa0e0d996
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/pull/7784'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/releases/tag/v3.1.0'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/security/advisories/GHSA-qfmh-fph3-mw8q'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/security/advisories/GHSA-qfmh-fph3-mw8q'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00464
epssPercentile: 0.37448
ingestedAt: '2026-09-09T21:22:45.543Z'
---

## Overview

Etherpad is a real-time collaborative editor. From 2.1.0 until 3.1.0, Etherpad's src/node/handler/APIHandler.ts authorizes requests to /api/2/* in the authorization_code OAuth path by using requiredClaims with the admin claim. This check requires only that the claim exists, while src/node/security/OAuth2Provider.ts issues admin: false for configured non-admin users. A non-admin user with a valid signed token can therefore invoke administrative functions including setHTML, setText, appendText, deletePad, copyPad, movePad, restoreRevision, anonymizeAuthor, listAllPads, and listAuthorsOfPad, allowing disclosure, modification, or deletion of pads across the instance. This issue is fixed in version 3.1.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.