Server-Side Request Forgery (SSRF) in Easy!Appointments - CVE-2026-52840
Published: June 15, 2026
Vulnerability identifier: #VU134525
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-52840
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to disclose sensitive information about the deployment's internal network.
The vulnerability exists due to server-side request forgery in Caldav::connect_to_server when processing a user-supplied caldav_url. A remote privileged user can send a specially crafted request to disclose sensitive information about the deployment's internal network.
The returned error message can include the upstream status code and a small portion of the response body, making the SSRF semi-blind.
Affected software
Easy!Appointments
How to mitigate CVE-2026-52840
Install security update from vendor's website.
Easy!Appointments - update to 1.6.0