Joplin: Fountain embeds allow arbitrary script execution in published notes and the note viewer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55105
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-21 21:17:05 UTC
Updated2026-09-24 23:17:11 UTC
DescriptionJoplin 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.

Risk And Classification

Primary CVSS: v3.1 7.7 HIGH from [email protected]

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

EPSS: 0.004950000 probability, percentile 0.400200000 (date 2026-09-27)

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
3.1CNADECLARED7.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Laurent22 Joplin affected < 3.6.15 Not specified
CNA Laurent22 Joplin affected >= 3.7.0, < 3.7.2 Not specified

References

ReferenceSourceLinkTags
github.com/laurent22/joplin/commit/8e0812de9d79d1f0698bb76a8c5d7e991df9748d [email protected] github.com
github.com/laurent22/joplin/security/advisories/GHSA-f7q3-3grx-6wg9 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/laurent22/joplin/pull/15659 [email protected] github.com
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