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Description

Notesnook is a note-taking app focused on user privacy & ease of use. Prior to version 3.3.17, a stored XSS vulnerability exists in the mobile share / web clip flow because attacker-controlled clip metadata is concatenated into HTML without escaping and then rendered with innerHTML inside the mobile share editor WebView. An attacker can control the shared title metadata (for example through Android/iOS share metadata such as TITLE / SUBJECT, or through link-preview title data) and inject HTML such as </a><img src=x onerror=...>. When the victim opens the Notesnook share flow and selects Web clip, the payload is inserted into the generated HTML and executed in the mobile editor WebView. This issue has been patched in version 3.3.17.

PUBLISHED Reserved 2026-03-24 | Published 2026-04-01 | Updated 2026-04-01 | Assigner GitHub_M




MEDIUM: 5.4CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Problem types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Product status

< 3.3.17
affected

References

github.com/...esnook/security/advisories/GHSA-f27j-fqc6-v7pm

github.com/...ommit/fc8807f74db5539036c5e58d3d68a11ea54098db

github.com/...twriters/notesnook/releases/tag/3.3.17-android

cve.org (CVE-2026-33978)

nvd.nist.gov (CVE-2026-33978)

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