Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Streetwriters | Notesnook Mobile | < 3.3.17 |
Related Weaknesses (CWE)
References
- https://github.com/streetwriters/notesnook/commit/fc8807f74db5539036c5e58d3d68a1Patch
- https://github.com/streetwriters/notesnook/releases/tag/3.3.17-androidRelease Notes
- https://github.com/streetwriters/notesnook/security/advisories/GHSA-f27j-fqc6-v7ExploitVendor Advisory
FAQ
What is CVE-2026-33978?
CVE-2026-33978 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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 me...
How severe is CVE-2026-33978?
CVE-2026-33978 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-33978?
Check the references section above for vendor advisories and patch information. Affected products include: Streetwriters Notesnook Mobile.