RCE in Calcom Cal.diy
CVE-2025-71389
Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundles a version of Next.js whose React Server Components (RSC) request handling deserializes attacker-controlled input. A remote attacker can send a crafted RSC request to the server and cause arbitrary code to be executed during server-side processing, without authentication or user interaction. The flaw derives from the upstream Next.js vulnerability CVE-2025-55182 and is resolved in 5.9.9 by updating the affected dependency.
Vulnerability class: RCE (Remote Code Execution)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.014 (71.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.014 · change: +0.002
Affected products
- Calcom Cal.diy — versions 0, 5.9.9
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/calcom/cal.diy/security/advisories/GHSA-qjx2-5xqp-cpf4 (vendor-advisory)
- github.com/calcom/cal.diy/pull/25592 (issue-tracking, patch)
- github.com/advisories/GHSA-9qr9-h5gf-34mp (related)
- www.vulncheck.com/advisories/cal-com-before-remote-code-execution-via-rsc (third-party-advisory)
Frequently asked questions
- What is CVE-2025-71389?
- CVE-2025-71389 is a critical-severity vulnerability in Calcom Cal.diy, classified under Code Injection. CVSS score: 10.0/10. Published 2026-07-23.
- How severe is CVE-2025-71389?
- Critical severity. CVSS v3 base score is 10.0 out of 10.
- Is CVE-2025-71389 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.