CVE-2026-59814: XSS (CVSS 7.6)

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.

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CVSS v3.1 Score

7.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/laurent22/joplin/commit/920cd8f463bf9bbce9daa07581676123007118e5 https://github.com/laurent22/joplin/pull/15787 https://github.com/laurent22/joplin/security/advisories/GHSA-mx98-7h4g-6gmh https://github.com/laurent22/joplin/security/advisories/GHSA-mx98-7h4g-6gmh

Frequently Asked Questions

What is CVE-2026-59814? +

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. It has a CVSS v3.1 base score of 7.6 (HIGH).

How severe is CVE-2026-59814? +

CVE-2026-59814 has a CVSS v3.1 score of 7.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-59814? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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