Read the docs
TI-2026-39804 Aliases CVE-2026-55105

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

Priority HIGH 67CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00495 42nd percentileScored 2026-11-07
Fix Fixed joplin (laurent22): 3.6.15, 3.7.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
laurent22joplinbefore 3.6.15; 3.7.0 to before 3.7.23.6.15, 3.7.2Patch availableCNA
  • joplin Vendorlaurent22 Affected before 3.6.15; 3.7.0 to before 3.7.2 Fixed in 3.6.15, 3.7.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:joplin_project:joplin:*:*:*:*:*:*:*:*——laurent22
  • cpe:2.3:a:joplin_project:joplin:*:*:*:*:*:*:*:* Versions — — ·laurent22

Remediation

  • Fix · CNA joplin (laurent22) Fixed in 3.6.15, 3.7.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55105

References

Other 3

  • TI-2023-24472 Arbitrary code execution on click of PDF links in Joplin CVSS 3.1CRITICAL 9.0
  • TI-2024-32950 Remote Code Execution on click of <a> Link in markdown preview CVSS 3.1CRITICAL 9.6
  • TI-2024-27054 Joplin has a parsing error leading to Cross-site Scripting (XSS) CVSS 3.1CRITICAL 9.7
  • TI-2026-34297 Joplin: SSO Auth Code Login Missing Rate Limiting — 9-Digit Numeric Code Brute-Forceable via Unprotected Endpoint CVSS 4.0CRITICAL 9.1
  • TI-2025-17795 Cross-site Scripting (XSS) in Rich Text Editor allows arbitrary code execution in Joplin CVSS 3.1CRITICAL 9.6
  • TI-2025-19991 Privilege escalation in Joplin server via user patch endpoint CVSS 3.1HIGH 8.8
See all 39 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences