XSS in Marimo-Team Marimo
CVE-2026-54386
marimo before 0.23.9 contains a reflected cross-site scripting vulnerability in the notebook page that allows unauthenticated attackers to inject arbitrary JavaScript by exploiting improper escaping of single quotes in the file query parameter reflected into an inline JavaScript string literal. Attackers can craft a malicious link with a payload beginning with __new__ to bypass the 404 check and inject JavaScript into the page, which executes without Content-Security-Policy restrictions in the origin of a victim's marimo server.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (15.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Marimo-team Marimo — versions 0
Weakness classification (CWE)
References
- disclosure@vulncheck.com (release-notes)
- disclosure@vulncheck.com (issue-tracking)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-54386?
- CVE-2026-54386 is a medium-severity vulnerability in Marimo-Team Marimo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-06-17.
- How severe is CVE-2026-54386?
- Medium severity. CVSS v3 base score is 6.1 out of 10.