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NVD / CVE Program· CNA GitHub_M

CVE-2026-49449: Joplin: KaTeX `trust:true` enables URL-allowlist bypass leading to NTLMv2 credential theft via UNC path on Windows

Noroxi assessment

Priority: Monitor (action score 10/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: laurent22 joplin 3.7.2.

Low priority for now. Upgrade to laurent22 joplin 3.7.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. From 1.4.0 until 3.7.2, packages/renderer/MdToHtml/rules/katex.ts enables KaTeX's trust option for note content, allowing a note author to place a \href URL into rendered output without passing Joplin's normal URL allowlist. On Windows, clicking a link whose target is an attacker-controlled UNC path causes pathExists() to initiate SMB authentication and disclose the current user's NTLMv2 challenge-response without a warning. The unfiltered URL can also invoke other registered URL handlers, but the credential disclosure through KaTeX \href is the distinguishing demonstrated impact. This issue is fixed in version 3.7.2.

LowCVSS 2.5 · v3.1—No exploit Fix available
Published
Sep 21, 2026
Updated
Sep 28, 2026
EPSS
0.1% · 9th percentile

Report tools

JSON

Action score

10

Monitor

Low priority for now.

CVSS
10 / 40 · 2.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
2.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • laurent22 joplin

    • >= 1.4.0, < 3.7.2affected

Same product

laurent22: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-46649Joplin: SSO Auth Code Login Missing Rate Limiting — 9-Digit Numeric Code Brute-Forceable via Unprotected Endpoint
    36Monitor
  • CVE-2026-105786Joplin: Unauthenticated account takeover via an attacker-chosen application-authorisation identifier
    34Monitor
  • CVE-2026-105783Joplin Web Clipper pairing allows cross-origin theft of a permanent API token
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-59814Sep 21, 2026 · Joplin: Stored XSS via inline-served note attachment on published shares
    30Monitor
  • ← EarlierCVE-2026-59815Sep 21, 2026 · Joplin: Pending share recipients can write items into shared folders before accepting invitations
    17Monitor
  • Later →CVE-2026-46650Sep 21, 2026 · Joplin: Stored XSS in public share viewer via javascript: URL bypass in isAcceptedUrl
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
laurent22 joplin3.7.2 · descriptionVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-34600125 days apartJoplin Server delta API returns note content after share access is revoked
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Local
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVSS vector

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

nvd-secondary

Root cause

The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.

The bug in code

The whole CWE-200 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

json
{  "permissions": ["tabs", "<all_urls>"],  "background": { "service_worker": "analytics.js" }}

Fixed

json
{  "permissions": ["activeTab"],  "host_permissions": ["https://yildiz.example/*"]}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓
  2. SSVC exploitation— → poc

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records