CVE-2026-9304: calcom cal.diy Server-Side Request Forgery (SSRF)

Vulnerability summary

CVE-2026-9304 is a medium (CVSS 5.0) Server-Side Request Forgery (SSRF) vulnerability in calcom cal.diy. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.7% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 23-05-2026
   PublishedVulnerability first disclosed.
2. 26-05-2026
   Last modifiedVulnerability information updated.

Description

A security flaw has been discovered in calcom cal.diy up to 4.9.4. The affected element is the function validateUrlForSSRF of the file apps/web/app/api/logo/route.ts of the component Logo API. The manipulation results in server-side request forgery. It is possible to launch the attack remotely. Attacks of this nature are highly complex. The exploitability is described as difficult. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

• CWE-918Server-Side Request Forgery (SSRF)The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.