---
id: CVE-2026-55085
title: Etherpad is a real-time collaborative editor
summary: >-
  Etherpad is a real-time collaborative editor. Prior to 3.3.1,
  result.appendSpan in src/static/js/domline.ts interpolates the start attribute
  of a numbered list directly into an unquoted ol start attribute before
  assigning the generated m…
severity: critical
cvss: 9.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L'
cwe:
  - CWE-79
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-2026-55085'
references:
  - url: >-
      https://github.com/ether/etherpad/commit/d828185efcac9abc2e46e6da1c171393500fa319
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/pull/7937'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/releases/tag/v3.3.1'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/security/advisories/GHSA-f7h5-v9hm-548j'
    label: security-advisories@github.com
  - url: 'https://github.com/ether/etherpad/security/advisories/GHSA-f7h5-v9hm-548j'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00473
epssPercentile: 0.38244
ingestedAt: '2026-09-09T21:22:45.542Z'
---

## Overview

Etherpad is a real-time collaborative editor. Prior to 3.3.1, result.appendSpan in src/static/js/domline.ts interpolates the start attribute of a numbered list directly into an unquoted ol start attribute before assigning the generated markup to node.innerHTML. ImportEtherpad.setPadRaw in src/node/utils/ImportEtherpad.ts accepts attacker-controlled attribute-pool values from a crafted .etherpad import, including list:number1 and a malicious start value. Any user with write access to a pad can store markup that executes as cross-site scripting when another user opens the pad or /timeslider, including when an administrator views the pad. This issue is fixed in version 3.3.1.

## Remediation

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