# CVE-2021-37916: Joplin Cross-site Scripting in notes via form elements

Source: https://junglewise.ai/threats/cve-2021-37916-joplin-cross-site-scripting-in-notes-via-form-elements  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-05-24. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2021-37916 · Severity: low · CVSS 3.1 · Published 2022-05-24

Joplin is a free and open-source note-taking application available across desktop and mobile platforms. A vulnerability in versions before 2.0.9 allows attackers to inject malicious code through button and form elements embedded in note text, which is then executed in a user's browser when they view the affected note. This could allow an attacker to steal a user's session data, credentials, or manipulate the contents of their notes.

Technologies: [Joplin](https://junglewise.ai/threats/technologies/joplin). Vendors: [Joplin](https://junglewise.ai/threats/vendors/joplin).

## Quick answers

**Is CVE-2021-37916 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-37916 being exploited in the wild.

**How severe is CVE-2021-37916?** Low severity, with a CVSS score of 3.1, published 24 May 2022.

**Which products and versions are affected?** Joplin before 2.0.9.

**Is there a fix for CVE-2021-37916?** A patch was published on 2021: Fixed in version 2.0.9 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-37916 attacked?** It is attacked over the network.

**Am I affected by CVE-2021-37916?** Check whether you run Joplin at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

Joplin before 2.0.9 contains a Cross-site Scripting (XSS) vulnerability (CWE-79) in the note rendering engine that fails to properly filter form-related HTML elements (button, form, input, select, textarea, option, optgroup) from note bodies. An attacker can craft a note containing malicious form elements with event handlers or attributes that execute arbitrary JavaScript when the note is rendered. The attack requires user interaction (opening a malicious note) but no authentication is required for note creation if sharing is enabled. The vulnerability affects both the desktop and mobile applications. The fix, applied in version 2.0.9, adds these form elements to the disallowed tags list in the HTML sanitization logic.

## Affected products

- Joplin Joplin before 2.0.9

## Identifiers

- CVE-2021-37916
- GHSA-mrmf-755g-w2vw

## Timeline

- 2021-08-03: disclosed
- 2022-05-24: advisory
- 2021: patched: Fixed in version 2.0.9

## References

- [https://github.com/laurent22/joplin/commit/feaecf765368f2c273bea3a9fa641ff0da7e6b26](https://github.com/laurent22/joplin/commit/feaecf765368f2c273bea3a9fa641ff0da7e6b26)

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- [Joplin CSS injection in whiteboard text and file nodes](https://junglewise.ai/threats/cve-2026-105784-joplin-is-an-open-source-note-taking-and-to-do-application-that)
- [Joplin XSS vulnerability in HTML note links](https://junglewise.ai/threats/cve-2026-46650-joplin-is-an-open-source-note-taking-and-to-do-application-that)
- [Joplin cross-site scripting in Fountain code blocks](https://junglewise.ai/threats/cve-2026-55105-joplin-is-an-open-source-note-taking-and-to-do-application-that)
- [Joplin path traversal in resource synchronization](https://junglewise.ai/threats/cve-2026-49453-joplin-is-an-open-source-note-taking-and-to-do-application-that)
- [Joplin denial of service via uncontrolled resource allocation in note titles](https://junglewise.ai/threats/cve-2025-57798-joplin-denial-of-service-via-uncontrolled-resource-allocation-in)