What is CVE-2026-33978?

CVE-2026-33978 is a medium-severity vulnerability in Streetwriters Notesnook, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-01.

How severe is CVE-2026-33978?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Streetwriters Notesnook

CVE-2026-33978

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 withou…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.000 (14.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

Affected products

Streetwriters Notesnook — versions < 3.3.17

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

https://github.com/streetwriters/notesnook/security/advisories/GHSA-f27j-fqc6-v7pm (x_refsource_CONFIRM)
https://github.com/streetwriters/notesnook/commit/fc8807f74db5539036c5e58d3d68a11ea54098db (x_refsource_MISC)
https://github.com/streetwriters/notesnook/releases/tag/3.3.17-android (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33978?: CVE-2026-33978 is a medium-severity vulnerability in Streetwriters Notesnook, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-01.
How severe is CVE-2026-33978?: Medium severity. CVSS v3 base score is 5.4 out of 10.