CVE-2026-59814: Joplin: Stored XSS via inline-served note attachment on published shares

Severity: high (CVSS 7.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-21 · updated 2026-09-23
Weakness: CWE-79

Description

Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.7, Joplin Server's GET /shares/:id?resource_id= route serves a resource with the attacker-controlled mime value and omits Content-Disposition when the resource title is empty. A low-privileged user can publish an empty-title image/svg+xml attachment whose script executes when a victim opens the public share. By default, user content shares the Joplin Server application origin, allowing the script to access same-origin data and, when the victim is authenticated, perform actions with the victim's session, including reading administrative data and anti-CSRF tokens. Installations that configure USER_CONTENT_BASE_URL to a separate origin still execute the script, but on that separate user-content origin rather than the application origin. This issue is fixed in version 3.7.7.

Affected products

laurent22 joplin: before 3.7.7

References

Get alerted when CVE-2026-59814 or the next vulnerability affects your stack