CVE-2023-39517: Cross site scripting (XSS) when clicking on an untrusted `<map>` link in Joplin

Vulnerability summary

CVE-2023-39517 is a high (CVSS 8.2) Cross-site Scripting vulnerability in joplin_project joplin. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 21-06-2024
   PublishedVulnerability first disclosed.
2. 02-08-2024
   Last modifiedVulnerability information updated.

Description

Joplin is a free, open source note taking and to-do application. A Cross site scripting (XSS) vulnerability in affected versions allows clicking on an untrusted image link to execute arbitrary shell commands. The HTML sanitizer (`packages/renderer/htmlUtils.ts::sanitizeHtml`) preserves `<map>` `<area>` links. However, unlike `<a>` links, the `target` and `href` attributes are not removed. Additionally, because the note preview pane isn't sandboxed to prevent top navigation, links with `target` set to `_top` can replace the toplevel electron page. Because any toplevel electron page, with Joplin's setup, has access to `require` and can require node libraries, a malicious replacement toplevel page can import `child_process` and execute arbitrary shell commands. This issue has been fixed in commit 7c52c3e9a81a52ef1b42a951f9deb9d378d59b0f which is included in release version 2.12.8. Users are advised to upgrade. There are no known workarounds for this vulnerability.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.