CVE-2026-55105

7.7 HIGHpublic exploit available

Published 2026-09-21 · Updated 2026-09-24

AI risk analysis

Summary: The flaw allows execution of malicious scripts in Joplin notes, posing a risk to user data integrity and confidentiality.
Exploitability: Exploitation requires a user to open a malicious note or have notes published with Fountain rendering enabled, making it moderately exploitable.
Blast radius: If exploited, attackers could read content from reused notes or access data in the server origin, impacting multiple users.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to Joplin version 3.6.15 or later.

rcewebnote-taking

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.6.15 and 3.7.2, packages/renderer/MdToHtml/rules/fountain.ts passes HTML generated by the vendored fountain.js renderer into note output without sanitizing it. A malicious Fountain code block can therefore execute script when Fountain rendering is enabled in desktop or mobile clients, or when a note is published through Joplin Server where Fountain rendering is enabled by default. The script can read content subsequently loaded in the reused note viewer or, when published notes are served from the same domain as server content, access data available to an authenticated browser in the server origin. This issue is fixed in versions 3.6.15 and 3.7.2.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Weaknesses

CWE-79

Public exploit & PoC references

References

Data: NVD (public domain). Analysis: local $0 model. Defensive use only.