CVE-2026-33955Public exploit

Code execution via unsanitized note-history titles

Published Mar 27, 2026 · Updated Mar 27, 2026

Stored XSS in Notesnook Web/Desktop before 3.3.11 allows attackers to execute code when a user opens a crafted note-history backup. The diff viewer passes attacker-controlled current and historical note titles to dangerouslySetInnerHTML, while the desktop Electron renderer exposes Node.js APIs because nodeIntegration is enabled and contextIsolation is disabled. Exploitation requires a desktop user to restore an attacker-supplied full backup, open the imported note's history, and select an entry; the web client is limited to stored script execution.

CVSS severity8.6
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Notesnook Web/Desktop before 3.3.11 allows attackers to execute code when a user opens a crafted note-history backup. The diff viewer passes attacker-controlled current and historical note titles to dangerouslySetInnerHTML, while the desktop Electron renderer exposes Node.js APIs because nodeIntegration is enabled and contextIsolation is disabled. Exploitation requires a desktop user to restore an attacker-supplied full backup, open the imported note's history, and select an entry; the web client is limited to stored script execution.

The record

CVE
CVE-2026-33955
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Streetwriters
Product
Notesnook
Classifications
CWE-79, CWE-94, T1203, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.3.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Streetwriters · Notesnookversion=< 3.3.11

Published CVSS scores

8.6GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-94Improper Control of Generation of Code ('Code Injection')
T1203Exploitation for Client Execution
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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