CVE-2026-55105

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.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: HIGH
CVSS score: 7.7 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Effective score: 7.7 / 10 HIGH source: CNA overview
CWE(s): CWE-79
Reserved: 2026-06-16
Published: 2026-09-21 20:59 UTC
Last updated: 2026-09-21 20:59 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/55xxx/CVE-2026-55105.json
Linked Threat: CVE-2026-55105 — Joplin: Fountain embeds allow arbitrary script execution in published notes and the note viewer

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-21 21:17:05 UTC
NVD last modified: 2026-09-21 21:17:05 UTC
NVD CVSS v3.1: 7.7 / 10 HIGH source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Exploitability subscore: 3.1 / 10
Impact subscore: 4.0 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84172
Assigner: GitHub_M
Published: Sep 21, 2026, 8:59:52 PM
Updated: Sep 21, 2026, 8:59:52 PM
EUVD base score (CVSS 3.1): 7.7 / 10
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
EUVD-reported EPSS: 0.0000
Vendors: laurent22
Products: joplin (3.7.0, < 3.7.2)

joplin (< 3.6.15)

ENISA 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.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
laurent22	joplin	`< 3.6.15` (affected), `>= 3.7.0, < 3.7.2` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

https://github.com/laurent22/joplin/security/advisories/GHSA-f7q3-3grx-6wg9 x_refsource_CONFIRM
https://github.com/laurent22/joplin/pull/15659 x_refsource_MISC
https://github.com/laurent22/joplin/commit/8e0812de9d79d1f0698bb76a8c5d7e991df9748d x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/laurent22/joplin/commit/8e0812de9d79d1f0698bb76a8c5d7e991df9748d security-advisories@github.com
https://github.com/laurent22/joplin/pull/15659 security-advisories@github.com
https://github.com/laurent22/joplin/security/advisories/GHSA-f7q3-3grx-6wg9 security-advisories@github.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-55010: what Bedrock server admins actually need to do

web:mcreference.com

Home / Guides / CVE - 2026 -55010: what Bedrock server admins actually need to do Guide for server owners · 3 min read CVE - 2026 -55010: what Bedrock server admins actually need to do A critical, unauthenticated remote code execution flaw in Bedrock Dedicated Server, CVSS 9.8. What it actually is, what Microsoft's own patch data says about it, and the one thing that matters regardless of how it's ...

2026-09-22 16:48 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-22 16:48 UTC
Cisco Advance Notification for Publication of September 16, 2026 ...

web:sec.cloudapps.cisco.com

On September 16, 2026 , the Cisco Product Security Incident Response Team (PSIRT) published the advisories that are listed in the following tables. To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories. For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the ...

2026-09-22 16:48 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-22 16:48 UTC
Description of the security update for Microsoft Exchange Server ...

web:support.microsoft.com

Description of the security update for Microsoft Exchange Server Subscription Edition RTM August 11, 2026 (KB5121573)

2026-09-22 16:48 UTC
SAP Security Patch Day - April 2026

web:support.sap.com

SAP security patch day bulletin This post shares the information on security notes that remediate vulnerabilities discovered in SAP products. SAP strongly recommends that the customer visits the support portal and applies patches on priority to protect their SAP landscape. On 14 th of April 2026 , SAP security patch day saw the release of 19 new security notes. There is 1 update to previously ...

2026-09-22 16:48 UTC
SAP Security Patch Day - May 2026

web:support.sap.com

SAP security Patch Day Bulletin This post shares the information on security notes that remediate vulnerabilities discovered in SAP products. SAP strongly recommends that the customer visits the support portal and applies patches on priority to protect their SAP landscape. On 12 th of May 2026 , SAP security patch day saw the release of 15 new security notes.

2026-09-22 16:48 UTC
July 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft has released security updates for 622 vulnerabilities in its July 2026 Patch Tuesday rollout.

2026-09-22 16:48 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 16:48 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 16:48 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-55105.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "joplin",
          "vendor": "laurent22",
          "versions": [
            {
              "status": "affected",
              "version": "< 3.6.15"
            },
            {
              "status": "affected",
              "version": ">= 3.7.0, < 3.7.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T20:59:52.292Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/laurent22/joplin/security/advisories/GHSA-f7q3-3grx-6wg9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/laurent22/joplin/security/advisories/GHSA-f7q3-3grx-6wg9"
        },
        {
          "name": "https://github.com/laurent22/joplin/pull/15659",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/laurent22/joplin/pull/15659"
        },
        {
          "name": "https://github.com/laurent22/joplin/commit/8e0812de9d79d1f0698bb76a8c5d7e991df9748d",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/laurent22/joplin/commit/8e0812de9d79d1f0698bb76a8c5d7e991df9748d"
        }
      ],
      "source": {
        "advisory": "GHSA-f7q3-3grx-6wg9",
        "discovery": "UNKNOWN"
      },
      "title": "Joplin: Fountain embeds allow arbitrary script execution in published notes and the note viewer"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55105",
    "datePublished": "2026-09-21T20:59:52.292Z",
    "dateReserved": "2026-06-16T14:41:54.579Z",
    "dateUpdated": "2026-09-21T20:59:52.292Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}