Quick answers
- Is CVE-2026-59814 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-59814 being exploited in the wild.
- How severe is CVE-2026-59814?
- High severity, with a CVSS score of 7.6, published 21 September 2026.
- Which products and versions are affected?
- Joplin Server prior to 3.7.7.
- Is there a fix for CVE-2026-59814?
- A patch was published on 2026-06-28: Fix merged in commit 920cd8f Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-59814 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-59814?
- Check whether you run Joplin Server 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
The GET /shares/:id?resource_id= endpoint serves user-uploaded resources with an attacker-controlled MIME type and omits Content-Disposition headers when the resource title is empty, enabling stored XSS. An attacker can craft an SVG file (image/svg+xml) with embedded script and empty title; when rendered inline without proper headers and CSP, the script executes in the Joplin Server origin, allowing access to same-origin data and authenticated user sessions. The fix restricts inline MIME types to a whitelist (images, audio, video, PDF), forces other types to application/octet-stream with attachment disposition, and adds X-Content-Type-Options: nosniff and strict CSP headers.
Affected products
- Joplin Server prior to 3.7.7
Timeline
- 2026-09-21: disclosed
- 2026-06-28: patched: Fix merged in commit 920cd8f