How broadly exploitable is this vulnerability?

The vulnerability is exploitable wherever an attacker can influence note content that is later exported. In shared or multi-device scenarios, or if an account is compromised, an attacker can plant a malicious note that triggers when the user exports it to PDF, leading to stored XSS in all clients and RCE specifically in the desktop app.

Does an attacker need direct access to the victim's device?

Direct device access is not strictly required. The attacker mainly needs a path to inject malicious content into a note under the victim's account. Once the victim exports that note to PDF in a vulnerable desktop environment, the attacker's script can execute and potentially run arbitrary code on the victim's machine.

What is the safest high-level fix pattern for developers?

The safest pattern is to treat all note content and metadata as untrusted and enforce strict output encoding or sanitization at every point where this data is rendered into HTML. Additionally, untrusted content should be isolated (e.g., sandboxed iframes), and Electron configurations must follow secure defaults by disabling Node integration and enabling context isolation in renderer processes.

Severity:

CRITICAL RISK

(9.6)

Stored Cross-Site Scripting to RCE (CWE-79) in Notesnook Export Flow

CVE-2026-42090

Published:

May 4, 2026

Status:

Received

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

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Privilege Escalation via Bypassed Access Control

May 6, 2026

Vulnerability Type

Category:

Stored Cross-Site Scripting (XSS)

CWE:

CWE-79;CWE-94

Impact:

Remote Code Execution via Stored XSS in Desktop Application

Severity:

CRITICAL RISK

(9.6)

CVSS Version:

3.1

Vulnerability Type

Category:

Stored Cross-Site Scripting (XSS)

CWE:

CWE-79;CWE-94

Impact:

Remote Code Execution via Stored XSS in Desktop Application

Severity:

CRITICAL RISK

(9.6)

CVSS Version:

3.1

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Stored Cross-Site Scripting to RCE (CWE-79) in Notesnook Export Flow

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(8.6)

Server-Side Request Forgery (CWE-918) in OpenClaw Zalo Plugin sendPhoto

HIGH RISK

HIGH

(8.8)

Authorization Bypass (CWE-863) in OpenClaw Matrix Room Control Commands

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Ship clean & secure code faster

Ship clean & secure code faster

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