Etherpad: Stored XSS in HTML export via unescaped attribute-pool values (CVE-2026-55090) | HOL Guard CVE

High severityCVE-2026-55090GHSA-2JP7-WWPG-3P9W

Etherpad: Stored XSS in HTML export via unescaped attribute-pool values

Answer in brief

CVE-2026-55090 records a High severity vulnerability in Etherpad: Stored XSS in HTML export via unescaped attribute-pool values. The current sources do not mark it as known exploited. The current feed maps ether/etherpad (generic), ep_etherpad-lite (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 19, 2026Updated Aug 19, 2026Source checked Aug 19, 2026First seen by HOL Aug 17, 2026Material review Aug 19, 2026

Upstream Advisory

Key facts

Risk: High
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps ether/etherpad (generic), ep_etherpad-lite (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
ether/etherpadgeneric	< 3.3.0	Not reported
ep_etherpad-litenpm	<=1.8.14	3.3.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for ether/etherpad, ep_etherpad-lite.
Review the reported fix. Update ep_etherpad-lite to 3.3.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 17, 2026

Sources and claim methodology

Upstream source description

Etherpad is a real-time collaborative editor. Prior to 3.3.0, getHTMLFromAtext in src/node/utils/ExportHtml.ts interpolates values from the exportHtmlAdditionalTagsWithData plugin hook into span data attributes without HTML attribute escaping. A pad editor can place an attacker-controlled value into the attribute pool through moveOpsToNewPool and AttributePool.putAttrib. When a bundled plugin such as ep_font_color or ep_font_size registers the hook, opening the resulting HTML export causes the value to execute as stored cross-site scripting in the Etherpad origin. This issue is fixed in version 3.3.0.

Quoted source text, attributed separately from HOL analysis.