Vulnerability details
CVE-2026-55085
Etherpad: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in etherpad-lite
Official description
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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.6Critical | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| ether | etherpad | < 3.3.1 | CVEProject cvelistV5 (CNA) |
References and advisories
4- https://github.com/ether/etherpad/pull/7937 x_refsource_MISC
- https://github.com/ether/etherpad/commit/d828185efcac9abc2e46e6da1c171393500fa319 x_refsource_MISC
- https://github.com/ether/etherpad/releases/tag/v3.3.1 x_refsource_MISC
- https://github.com/ether/etherpad/security/advisories/GHSA-f7h5-v9hm-548j x_refsource_CONFIRM
Details
- Published
- 2026-08-19
- Last updated
- 2026-08-21
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')