Published: September 21, 2026 | Last Modified: September 21, 2026
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.2, isAcceptedUrl() in packages/renderer/htmlUtils.ts uses an unanchored regular expression for internal resource URLs, allowing a javascript: URL containing a matching 32-character path fragment to pass validation and be emitted into an HTML note's link. A low-privileged Joplin Server user can publish the crafted HTML note as a public share. In the current build, ordinary left-click is blocked; demonstrated execution requires middle-click or Open in new tab in an older or non-hardened browser because current Chrome and Firefox block javascript: new-tab navigation. When execution succeeds, the script runs in the Joplin Server origin, can read page-visible content, and can make authenticated same-origin requests when the victim is signed in. This issue is fixed in version 3.7.2.
Exploitation Probability (EPSS): Low — 0.23% (14th percentile)
Low exploitation probability based on current threat landscape data. Standard patching timeline is appropriate.
This analysis is generated by Ghostwire from NVD, CISA KEV, EPSS, and open-source intelligence data. Verify findings through primary sources before acting.