CVE-2026-33978
MEDIUMNotesnook: Stored XSS in mobile share editor via unescaped web clip title metadata
Title source: cnaDescription
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.
Scores
CVSS v3
5.4
EPSS
0.0003
EPSS Percentile
8.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-79
Status
published
Products (2)
streetwriters/notesnook
< 3.3.17
streetwriters/notesnook_mobile
< 3.3.17 (2 CPE variants)
Published
Apr 01, 2026
Tracked Since
Apr 01, 2026