CVE-2026-120350
Awaiting Analysis Awaiting Analysis - Queue

Stored XSS in Vaadin Rich Text Editor

Publication date: 2026-11-10

Last updated on: 2026-11-10

Assigner: Vaadin Ltd.

Description
The Vaadin Rich Text Editor exports a video embed without escaping its value, and then parses the resulting HTML into live DOM. A value crafted to break out of the href attribute therefore runs script in the viewer's browser. An attacker who can edit shared content pastes a video embed carrying the payload, the delta is stored, and the script runs when any user opens the page, including in read only mode. Only content persisted through asDelta() is affected. The default HTML value, set and read through setValue and getValue, is sanitized on the server with a safelist that has no iframe, so the embed does not survive that path. Vaadin 24 and older are not affected: they build the HTML value from the editor's own innerHTML, which the browser escapes. Users of affected versions should apply the following mitigation or upgrade. Releases that have fixed this issue include: Product version Vaadin 25.0.0 - 25.0.13 Vaadin 25.1.0 - 25.1.13 Vaadin 25.2.0 - 25.2.12 Vaadin 25.3.0 - 25.3.4 Mitigation No fixed release on this line, upgrade to 25.2.13 or newer No fixed release on this line, upgrade to 25.2.13 or newer Upgrade to 25.2.13 Upgrade to 25.3.5

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-11-10
Last Modified
2026-11-10
Generated
2026-11-10
AI Q&A
2026-11-10
EPSS Evaluated
N/A
NVD
CVE-2026-120350
EUVD
EUVD-2026-120894

Affected Vendors & Products

Showing 16 associated CPEs
Vendor Product Version / Range
vaadin vaadin From 25.0.0 (inc) to 25.0.13 (inc)
vaadin vaadin From 25.1.0 (inc) to 25.1.13 (inc)
vaadin vaadin From 25.2.0 (inc) to 25.2.13 (exc)
vaadin vaadin From 25.3.0 (inc) to 25.3.5 (exc)
vaadin vaadin-core From 25.0.0 (inc) to 25.0.13 (inc)
vaadin vaadin-core From 25.1.0 (inc) to 25.1.13 (inc)
vaadin vaadin-core From 25.2.0 (inc) to 25.2.13 (exc)
vaadin vaadin-core From 25.3.0 (inc) to 25.3.5 (exc)
vaadin vaadin-rich-text-editor-flow From 25.0.0 (inc) to 25.0.13 (inc)
vaadin vaadin-rich-text-editor-flow From 25.1.0 (inc) to 25.1.13 (inc)
vaadin vaadin-rich-text-editor-flow From 25.2.0 (inc) to 25.2.13 (exc)
vaadin vaadin-rich-text-editor-flow From 25.3.0 (inc) to 25.3.5 (exc)
vaadin rich-text-editor From 25.0.0 (inc) to 25.0.13 (inc)
vaadin rich-text-editor From 25.1.0 (inc) to 25.1.14 (inc)
vaadin rich-text-editor From 25.2.0 (inc) to 25.2.17 (exc)
vaadin rich-text-editor From 25.3.0 (inc) to 25.3.5 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability involves the Vaadin Rich Text Editor improperly escaping video embed URLs when exporting HTML. An attacker can craft a malicious URL that breaks out of the href attribute, executing arbitrary JavaScript in the viewer's browser when the page is opened. The issue only affects content processed through asDelta(), while default HTML values set via setValue/getValue are sanitized on the server.

Detection Guidance

Check if your Vaadin application uses versions 25.0.0 to 25.3.4 of the rich-text-editor. Inspect HTML output for video embeds with unescaped attributes. Use browser developer tools to examine DOM for script execution in video embeds.

Impact Analysis

An attacker could inject malicious scripts into shared content, which would execute when any user views the page, including in read-only mode. This could lead to unauthorized actions, data theft, or session hijacking for users interacting with the affected Vaadin Rich Text Editor component.

Compliance Impact

This XSS vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality principles or HIPAA's safeguards for protected health information. Organizations using affected Vaadin versions may face compliance violations if exploited.

Mitigation Strategies

Upgrade to Vaadin 25.2.13 or newer, or 25.3.5 or newer. If upgrading is not possible, apply the mitigation by ensuring video embeds are sanitized before rendering. Review shared content for malicious video embeds.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-120350. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart

Security Radar

News mentioning this vulnerability
Loading related security news...