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DOM-based Cross-Site Scripting (XSS) in Text Editor

Moderate
drfarrell published GHSA-w73g-vc27-2pg2 Dec 14, 2025

Package

No package listed

Affected versions

< 2025-12-14

Patched versions

>= 2025-12-14

Description

Impact

A DOM-based Cross-Site Scripting (XSS) vulnerability existed in the text editor feature. User input was directly injected into the DOM via innerHTML without sanitization, allowing attackers to inject and execute arbitrary JavaScript.

An attacker could craft malicious text content containing HTML/JavaScript (e.g., <script>alert(1)</script> or event handlers like <img onerror="...">) that would execute in the context of the preview iframe when rendered.

Severity: Medium - Attackers could execute arbitrary JavaScript in the victim's browser session within the editor context.

Patches

This vulnerability has been patched in commit 4dc2c0a305d384b6a016520d583514d73f224d50 (PR #3064).

The fix sanitizes user input by escaping HTML entities via textContent before DOM insertion, then safely converting newlines to <br> elements.

Users of the hosted Onlook service are automatically protected. Self-hosted users should pull the latest changes from the main branch.

Workarounds

There are no workarounds. Users must upgrade to a patched version.

References

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVE ID

CVE-2025-63785

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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. Learn more on MITRE.

Credits